diff --git a/lib/box/file.ts b/lib/box/file.ts
index 6171e430d6..99bb509ddd 100644
--- a/lib/box/file.ts
+++ b/lib/box/file.ts
@@ -1,10 +1,12 @@
-import { readFile, readFileSync, stat, statSync } from 'hexo-fs';
+import type Promise from 'bluebird';
+import { readFile, readFileSync, stat, statSync, type ReadFileOptions } from 'hexo-fs';
+import type fs from 'fs';
 
 class File {
-  public source: any;
-  public path: any;
+  public source: string;
+  public path: string;
   public params: any;
-  public type: any;
+  public type: string;
   static TYPE_CREATE: 'create';
   static TYPE_UPDATE: 'update';
   static TYPE_SKIP: 'skip';
@@ -17,19 +19,19 @@ class File {
     this.type = type;
   }
 
-  read(options) {
+  read(options?: ReadFileOptions): Promise<string | Buffer> {
     return readFile(this.source, options);
   }
 
-  readSync(options) {
+  readSync(options?: ReadFileOptions): string | Buffer {
     return readFileSync(this.source, options);
   }
 
-  stat(options) {
+  stat(): Promise<fs.Stats> {
     return stat(this.source);
   }
 
-  statSync(options) {
+  statSync(): fs.Stats {
     return statSync(this.source);
   }
 }
diff --git a/lib/box/index.ts b/lib/box/index.ts
index a61e08e54e..3222b55880 100644
--- a/lib/box/index.ts
+++ b/lib/box/index.ts
@@ -6,6 +6,7 @@ import { createReadStream, readdir, stat, watch } from 'hexo-fs';
 import { magenta } from 'picocolors';
 import { EventEmitter } from 'events';
 import { isMatch, makeRe } from 'micromatch';
+import type Hexo from '../hexo';
 
 const defaultPattern = new Pattern(() => ({}));
 
@@ -16,20 +17,18 @@ interface Processor {
 
 class Box extends EventEmitter {
   public options: any;
-  public context: any;
-  public base: any;
+  public context: Hexo;
+  public base: string;
   public processors: Processor[];
   public _processingFiles: any;
   public watcher: any;
   public Cache: any;
   // TODO: replace runtime class _File
   public File: any;
-  public ignore: any;
+  public ignore: any[];
   public source: any;
-  public emit: any;
-  public ctx: any;
 
-  constructor(ctx, base, options?: object) {
+  constructor(ctx: Hexo, base: string, options?: object) {
     super();
 
     this.options = Object.assign({
@@ -64,13 +63,13 @@ class Box extends EventEmitter {
     class _File extends File {
       public box: Box;
 
-      render(options) {
+      render(options?: object) {
         return ctx.render.render({
           path: this.source
         }, options);
       }
 
-      renderSync(options) {
+      renderSync(options?: object) {
         return ctx.render.renderSync({
           path: this.source
         }, options);
@@ -82,7 +81,9 @@ class Box extends EventEmitter {
     return _File;
   }
 
-  addProcessor(pattern, fn) {
+  addProcessor(pattern: (...args: any[]) => any): void;
+  addProcessor(pattern: string | RegExp | Pattern | ((...args: any[]) => any), fn: (...args: any[]) => any): void;
+  addProcessor(pattern: string | RegExp | Pattern | ((...args: any[]) => any), fn?: (...args: any[]) => any): void {
     if (!fn && typeof pattern === 'function') {
       fn = pattern;
       pattern = defaultPattern;
@@ -97,7 +98,7 @@ class Box extends EventEmitter {
     });
   }
 
-  _readDir(base, prefix = '') {
+  _readDir(base: string, prefix = ''): BlueBirdPromise<any> {
     const { context: ctx } = this;
     const results = [];
     return readDirWalker(ctx, base, results, this.ignore, prefix)
@@ -106,7 +107,7 @@ class Box extends EventEmitter {
       .map(file => this._processFile(file.type, file.path).return(file.path));
   }
 
-  _checkFileStatus(path) {
+  _checkFileStatus(path: string) {
     const { Cache, context: ctx } = this;
     const src = join(this.base, path);
 
@@ -120,7 +121,7 @@ class Box extends EventEmitter {
     }));
   }
 
-  process(callback?) {
+  process(callback?: NodeJSLikeCallback<any>): BlueBirdPromise<any> {
     const { base, Cache, context: ctx } = this;
 
     return stat(base).then(stats => {
@@ -132,14 +133,14 @@ class Box extends EventEmitter {
 
       // Handle deleted files
       return this._readDir(base)
-        .then(files => cacheFiles.filter(path => !files.includes(path)))
-        .map(path => this._processFile(File.TYPE_DELETE, path));
+        .then((files: string[]) => cacheFiles.filter((path: string) => !files.includes(path)))
+        .map((path: string) => this._processFile(File.TYPE_DELETE, path) as PromiseLike<any>);
     }).catch(err => {
       if (err && err.code !== 'ENOENT') throw err;
     }).asCallback(callback);
   }
 
-  _processFile(type, path) {
+  _processFile(type: string, path: string): BlueBirdPromise<void> | BlueBirdPromise<string> {
     if (this._processingFiles[path]) {
       return BlueBirdPromise.resolve();
     }
@@ -182,7 +183,7 @@ class Box extends EventEmitter {
     }).thenReturn(path);
   }
 
-  watch(callback?) {
+  watch(callback?: NodeJSLikeCallback<never>): BlueBirdPromise<void> {
     if (this.isWatching()) {
       return BlueBirdPromise.reject(new Error('Watcher has already started.')).asCallback(callback);
     }
@@ -217,24 +218,24 @@ class Box extends EventEmitter {
     }).asCallback(callback);
   }
 
-  unwatch() {
+  unwatch(): void {
     if (!this.isWatching()) return;
 
     this.watcher.close();
     this.watcher = null;
   }
 
-  isWatching() {
+  isWatching(): boolean {
     return Boolean(this.watcher);
   }
 }
 
-function escapeBackslash(path) {
+function escapeBackslash(path: string): string {
   // Replace backslashes on Windows
   return path.replace(/\\/g, '/');
 }
 
-function getHash(path) {
+function getHash(path: string): BlueBirdPromise<string> {
   const src = createReadStream(path);
   const hasher = createSha1Hash();
 
@@ -248,7 +249,7 @@ function getHash(path) {
   return finishedPromise.then(() => hasher.digest('hex'));
 }
 
-function toRegExp(ctx, arg) {
+function toRegExp(ctx: Hexo, arg: string): RegExp | null {
   if (!arg) return null;
   if (typeof arg !== 'string') {
     ctx.log.warn('A value of "ignore:" section in "_config.yml" is not invalid (not a string)');
@@ -262,11 +263,11 @@ function toRegExp(ctx, arg) {
   return result;
 }
 
-function isIgnoreMatch(path, ignore) {
+function isIgnoreMatch(path: string, ignore: string | any[]): boolean {
   return path && ignore && ignore.length && isMatch(path, ignore);
 }
 
-function readDirWalker(ctx, base, results, ignore, prefix) {
+function readDirWalker(ctx: Hexo, base: string, results: any[], ignore: any, prefix: string): BlueBirdPromise<any> {
   if (isIgnoreMatch(base, ignore)) return BlueBirdPromise.resolve();
 
   return BlueBirdPromise.map(readdir(base).catch(err => {
@@ -292,4 +293,10 @@ function readDirWalker(ctx, base, results, ignore, prefix) {
   });
 }
 
-export = Box;
+export interface _File extends File {
+  box: Box;
+  render(options?: any): any;
+  renderSync(options?: any): any;
+}
+
+export default Box;
diff --git a/lib/extend/console.ts b/lib/extend/console.ts
index c4af6322d7..a5b7868af9 100644
--- a/lib/extend/console.ts
+++ b/lib/extend/console.ts
@@ -51,7 +51,7 @@ class Console {
     return this.store[this.alias[name]];
   }
 
-  list() {
+  list(): Store {
     return this.store;
   }
 
@@ -66,7 +66,7 @@ class Console {
   register(name: string, desc: string, fn: AnyFn): void
   register(name: string, options: Option, fn: AnyFn): void
   register(name: string, desc: string, options: Option, fn: AnyFn): void
-  register(name: string, desc: string | Option | AnyFn, options?: Option | AnyFn, fn?: AnyFn) {
+  register(name: string, desc: string | Option | AnyFn, options?: Option | AnyFn, fn?: AnyFn): void {
     if (!name) throw new TypeError('name is required');
 
     if (!fn) {
diff --git a/lib/extend/deployer.ts b/lib/extend/deployer.ts
index d42d3d854c..ae88664cdc 100644
--- a/lib/extend/deployer.ts
+++ b/lib/extend/deployer.ts
@@ -17,15 +17,15 @@ class Deployer {
     this.store = {};
   }
 
-  list() {
+  list(): Store {
     return this.store;
   }
 
-  get(name: string) {
+  get(name: string): StoreFunction {
     return this.store[name];
   }
 
-  register(name: string, fn: StoreFunction) {
+  register(name: string, fn: StoreFunction): void {
     if (!name) throw new TypeError('name is required');
     if (typeof fn !== 'function') throw new TypeError('fn must be a function');
 
diff --git a/lib/extend/filter.ts b/lib/extend/filter.ts
index 78113d01c2..2af06fae87 100644
--- a/lib/extend/filter.ts
+++ b/lib/extend/filter.ts
@@ -38,7 +38,7 @@ class Filter {
   register(fn: StoreFunction, priority: number): void
   register(type: string, fn: StoreFunction): void
   register(type: string, fn: StoreFunction, priority: number): void
-  register(type: string | StoreFunction, fn?: StoreFunction | number, priority?: number) {
+  register(type: string | StoreFunction, fn?: StoreFunction | number, priority?: number): void {
     if (!priority) {
       if (typeof type === 'function') {
         priority = fn as number;
@@ -61,7 +61,7 @@ class Filter {
     store.sort((a, b) => a.priority - b.priority);
   }
 
-  unregister(type: string, fn: StoreFunction) {
+  unregister(type: string, fn: StoreFunction): void {
     if (!type) throw new TypeError('type is required');
     if (typeof fn !== 'function') throw new TypeError('fn must be a function');
 
@@ -75,7 +75,7 @@ class Filter {
     if (index !== -1) list.splice(index, 1);
   }
 
-  exec(type: string, data: any[], options: FilterOptions = {}) {
+  exec(type: string, data: any[], options: FilterOptions = {}): Promise<any> {
     const filters = this.list(type);
     if (filters.length === 0) return Promise.resolve(data);
 
diff --git a/lib/extend/generator.ts b/lib/extend/generator.ts
index 6360d1eb2c..2854f8f869 100644
--- a/lib/extend/generator.ts
+++ b/lib/extend/generator.ts
@@ -31,17 +31,17 @@ class Generator {
     this.store = {};
   }
 
-  list() {
+  list(): Store {
     return this.store;
   }
 
-  get(name: string) {
+  get(name: string): StoreFunction {
     return this.store[name];
   }
 
   register(fn: GeneratorFunction): void
   register(name: string, fn: GeneratorFunction): void
-  register(name: string | GeneratorFunction, fn?: GeneratorFunction) {
+  register(name: string | GeneratorFunction, fn?: GeneratorFunction): void {
     if (!fn) {
       if (typeof name === 'function') { // fn
         fn = name;
diff --git a/lib/extend/helper.ts b/lib/extend/helper.ts
index 7903557c97..f167282371 100644
--- a/lib/extend/helper.ts
+++ b/lib/extend/helper.ts
@@ -35,7 +35,7 @@ class Helper {
    * @param {String} name - The name of the helper plugin
    * @param {StoreFunction} fn - The helper plugin function
    */
-  register(name: string, fn: StoreFunction) {
+  register(name: string, fn: StoreFunction): void {
     if (!name) throw new TypeError('name is required');
     if (typeof fn !== 'function') throw new TypeError('fn must be a function');
 
diff --git a/lib/extend/injector.ts b/lib/extend/injector.ts
index fd1d09acdd..edb4a45094 100644
--- a/lib/extend/injector.ts
+++ b/lib/extend/injector.ts
@@ -24,15 +24,15 @@ class Injector {
     this.cache = new Cache();
   }
 
-  list() {
+  list(): Store {
     return this.store;
   }
 
-  get(entry: Entry, to = 'default') {
+  get(entry: Entry, to = 'default'): any[] {
     return Array.from(this.store[entry][to] || []);
   }
 
-  getText(entry: Entry, to = 'default') {
+  getText(entry: Entry, to = 'default'): string {
     const arr = this.get(entry, to);
     if (!arr || !arr.length) return '';
     return arr.join('');
@@ -42,7 +42,7 @@ class Injector {
     return this.cache.apply(`${entry}-size`, Object.keys(this.store[entry]).length);
   }
 
-  register(entry: Entry, value: string | (() => string), to = 'default') {
+  register(entry: Entry, value: string | (() => string), to = 'default'): void {
     if (!entry) throw new TypeError('entry is required');
     if (typeof value === 'function') value = value();
 
@@ -52,7 +52,7 @@ class Injector {
     entryMap[to] = valueSet;
   }
 
-  _getPageType(pageLocals) {
+  _getPageType(pageLocals): string {
     let currentType = 'default';
     if (pageLocals.__index) currentType = 'home';
     if (pageLocals.__post) currentType = 'post';
@@ -65,7 +65,7 @@ class Injector {
     return currentType;
   }
 
-  _injector(input, pattern, flag, isBegin = true, currentType) {
+  _injector(input: string, pattern: string | RegExp, flag: Entry, isBegin = true, currentType: string): string {
     if (input.includes(`hexo injector ${flag}`)) return input;
 
     const code = this.cache.apply(`${flag}-${currentType}-code`, () => {
@@ -81,7 +81,7 @@ class Injector {
     return input.replace(pattern, str => { return isBegin ? str + code : code + str; });
   }
 
-  exec(data, locals = { page: {} }) {
+  exec(data: string, locals = { page: {} }): string {
     const { page } = locals;
     const currentType = this._getPageType(page);
 
diff --git a/lib/extend/migrator.ts b/lib/extend/migrator.ts
index 2a149f191a..5ab0f7063e 100644
--- a/lib/extend/migrator.ts
+++ b/lib/extend/migrator.ts
@@ -14,15 +14,15 @@ class Migrator {
     this.store = {};
   }
 
-  list() {
+  list(): Store {
     return this.store;
   }
 
-  get(name: string) {
+  get(name: string): StoreFunction {
     return this.store[name];
   }
 
-  register(name: string, fn: StoreFunction) {
+  register(name: string, fn: StoreFunction): void {
     if (!name) throw new TypeError('name is required');
     if (typeof fn !== 'function') throw new TypeError('fn must be a function');
 
diff --git a/lib/extend/processor.ts b/lib/extend/processor.ts
index 0af6998494..ce73da1031 100644
--- a/lib/extend/processor.ts
+++ b/lib/extend/processor.ts
@@ -19,13 +19,13 @@ class Processor {
     this.store = [];
   }
 
-  list() {
+  list(): Store {
     return this.store;
   }
 
   register(fn: StoreFunction): void;
   register(pattern: patternType, fn: StoreFunction): void;
-  register(pattern: patternType | StoreFunction, fn?: StoreFunction) {
+  register(pattern: patternType | StoreFunction, fn?: StoreFunction): void {
     if (!fn) {
       if (typeof pattern === 'function') {
         fn = pattern;
diff --git a/lib/extend/renderer.ts b/lib/extend/renderer.ts
index c70e054f18..15f90c6de6 100644
--- a/lib/extend/renderer.ts
+++ b/lib/extend/renderer.ts
@@ -8,36 +8,36 @@ const getExtname = (str: string) => {
   return ext.startsWith('.') ? ext.slice(1) : ext;
 };
 
-interface StoreSyncFunction {
+export interface StoreFunctionData {
+  path?: any;
+  text?: string;
+  engine?: string;
+  toString?: any;
+  onRenderEnd?: any;
+}
+
+export interface StoreSyncFunction {
+  [x: string]: any;
   (
-    data: {
-      path?: string;
-      text: string;
-    },
+    data: StoreFunctionData,
     options: object,
-    // callback: (err: Error, value: string) => any
+    // callback: NodeJSLikeCallback<string>
   ): any;
   output?: string;
-  compile?: (local: object) => string;
+  compile?: (local: object) => any;
 }
-interface StoreFunction {
+export interface StoreFunction {
   (
-    data: {
-      path?: string;
-      text: string;
-    },
+    data: StoreFunctionData,
     options: object,
   ): Promise<any>;
   (
-    data: {
-      path?: string;
-      text: string;
-    },
+    data: StoreFunctionData,
     options: object,
-    callback: (err: Error, value: string) => any
+    callback: NodeJSLikeCallback<string>
   ): void;
   output?: string;
-  compile?: (local: object) => string;
+  compile?: (local: object) => any;
   disableNunjucks?: boolean;
 }
 
@@ -57,25 +57,25 @@ class Renderer {
     this.storeSync = {};
   }
 
-  list(sync: boolean) {
+  list(sync: boolean): Store | SyncStore {
     return sync ? this.storeSync : this.store;
   }
 
-  get(name: string, sync?: boolean) {
+  get(name: string, sync?: boolean): StoreSyncFunction | StoreFunction {
     const store = this[sync ? 'storeSync' : 'store'];
 
     return store[getExtname(name)] || store[name];
   }
 
-  isRenderable(path: string) {
+  isRenderable(path: string): boolean {
     return Boolean(this.get(path));
   }
 
-  isRenderableSync(path: string) {
+  isRenderableSync(path: string): boolean {
     return Boolean(this.get(path, true));
   }
 
-  getOutput(path: string) {
+  getOutput(path: string): string {
     const renderer = this.get(path);
     return renderer ? renderer.output : '';
   }
@@ -109,4 +109,4 @@ class Renderer {
   }
 }
 
-export = Renderer;
+export default Renderer;
diff --git a/lib/extend/syntax_highlight.ts b/lib/extend/syntax_highlight.ts
index 419a950f24..c5cf28a95f 100644
--- a/lib/extend/syntax_highlight.ts
+++ b/lib/extend/syntax_highlight.ts
@@ -3,7 +3,7 @@ import type Hexo from '../hexo';
 export interface HighlightOptions {
   lang: string | undefined,
   caption: string | undefined,
-  lines_length: number,
+  lines_length?: number | undefined,
 
   // plugins/filter/before_post_render/backtick_code_block
   firstLineNumber?: string | number
@@ -39,13 +39,13 @@ class SyntaxHighlight {
     this.store = {};
   }
 
-  register(name: string, fn: StoreFunction) {
+  register(name: string, fn: StoreFunction): void {
     if (typeof fn !== 'function') throw new TypeError('fn must be a function');
 
     this.store[name] = fn;
   }
 
-  query(name: string) {
+  query(name: string): StoreFunction {
     return name && this.store[name];
   }
 
diff --git a/lib/extend/tag.ts b/lib/extend/tag.ts
index f2fcc3d325..d44b5dd993 100644
--- a/lib/extend/tag.ts
+++ b/lib/extend/tag.ts
@@ -4,7 +4,7 @@ import { Environment } from 'nunjucks';
 import Promise from 'bluebird';
 const rSwigRawFullBlock = /{% *raw *%}/;
 const rCodeTag = /<code[^<>]*>[\s\S]+?<\/code>/g;
-const escapeSwigTag = str => str.replace(/{/g, '&#123;').replace(/}/g, '&#125;');
+const escapeSwigTag = (str: string) => str.replace(/{/g, '&#123;').replace(/}/g, '&#125;');
 
 interface TagFunction {
   (args: any[], content: string): string;
@@ -66,7 +66,7 @@ class NunjucksTag {
   }
 }
 
-const trimBody = body => {
+const trimBody = (body: () => any) => {
   return stripIndent(body()).replace(/^\n?|\n?$/g, '');
 };
 
@@ -126,7 +126,7 @@ class NunjucksAsyncBlock extends NunjucksBlock {
   }
 }
 
-const getContextLineNums = (min, max, center, amplitude) => {
+const getContextLineNums = (min: number, max: number, center: number, amplitude: number) => {
   const result = [];
   let lbound = Math.max(min, center - amplitude);
   const hbound = Math.min(max, center + amplitude);
@@ -136,7 +136,7 @@ const getContextLineNums = (min, max, center, amplitude) => {
 
 const LINES_OF_CONTEXT = 5;
 
-const getContext = (lines, errLine, location, type) => {
+const getContext = (lines: string[], errLine: number, location: string, type: string) => {
   const message = [
     location + ' ' + red(type),
     cyan('    =====               Context Dump               ====='),
@@ -173,7 +173,7 @@ class NunjucksError extends Error {
  * @param  {string}   str string input for Nunjucks
  * @return {Error}    New error object with embedded context
  */
-const formatNunjucksError = (err, input, source = '') => {
+const formatNunjucksError = (err: Error, input: string, source = ''): Error => {
   err.message = err.message.replace('(unknown path)', source ? magenta(source) : '');
 
   const match = err.message.match(/Line (\d+), Column \d+/);
@@ -199,8 +199,8 @@ type RegisterOptions = {
 }
 
 class Tag {
-  public env: any;
-  public source: any;
+  public env: Environment;
+  public source: string;
 
   constructor() {
     this.env = new Environment(null, {
@@ -211,7 +211,7 @@ class Tag {
   register(name: string, fn: TagFunction): void
   register(name: string, fn: TagFunction, ends: boolean): void
   register(name: string, fn: TagFunction, options: RegisterOptions): void
-  register(name: string, fn: TagFunction, options?: RegisterOptions | boolean) {
+  register(name: string, fn: TagFunction, options?: RegisterOptions | boolean):void {
     if (!name) throw new TypeError('name is required');
     if (typeof fn !== 'function') throw new TypeError('fn must be a function');
 
@@ -243,7 +243,7 @@ class Tag {
     this.env.addExtension(name, tag);
   }
 
-  unregister(name) {
+  unregister(name: string): void {
     if (!name) throw new TypeError('name is required');
 
     const { env } = this;
@@ -251,7 +251,7 @@ class Tag {
     if (env.hasExtension(name)) env.removeExtension(name);
   }
 
-  render(str, options: { source?: string } = {}, callback) {
+  render(str: string, options: { source?: string } = {}, callback?: NodeJSLikeCallback<any>): Promise<any> {
     if (!callback && typeof options === 'function') {
       callback = options;
       options = {};
diff --git a/lib/hexo/index.ts b/lib/hexo/index.ts
index 2d347c7bde..c248b7b675 100644
--- a/lib/hexo/index.ts
+++ b/lib/hexo/index.ts
@@ -36,16 +36,17 @@ import defaultConfig from './default_config';
 import loadDatabase from './load_database';
 import multiConfigPath from './multi_config_path';
 import { deepMerge, full_url_for } from 'hexo-util';
+import type Box from '../box';
 let resolveSync; // = require('resolve');
 
 const libDir = dirname(__dirname);
 const dbVersion = 1;
 
-const stopWatcher = box => { if (box.isWatching()) box.unwatch(); };
+const stopWatcher = (box: Box) => { if (box.isWatching()) box.unwatch(); };
 
 const routeCache = new WeakMap();
 
-const castArray = obj => { return Array.isArray(obj) ? obj : [obj]; };
+const castArray = (obj: any) => { return Array.isArray(obj) ? obj : [obj]; };
 
 const mergeCtxThemeConfig = ctx => {
   // Merge hexo.config.theme_config into hexo.theme.config before post rendering & generating
@@ -335,7 +336,7 @@ class Hexo extends EventEmitter {
     });
   }
 
-  call(name, args, callback) {
+  call(name: string, args: any, callback?: NodeJSLikeCallback<any>) {
     if (!callback && typeof args === 'function') {
       callback = args;
       args = {};
@@ -348,11 +349,11 @@ class Hexo extends EventEmitter {
     return Promise.reject(new Error(`Console \`${name}\` has not been registered yet!`));
   }
 
-  model(name, schema) {
+  model(name: string, schema?: any) {
     return this.database.model(name, schema);
   }
 
-  resolvePlugin(name, basedir) {
+  resolvePlugin(name: string, basedir: string) {
     try {
       // Try to resolve the plugin with the Node.js's built-in require.resolve.
       return require.resolve(name, { paths: [basedir] });
@@ -370,18 +371,18 @@ class Hexo extends EventEmitter {
     }
   }
 
-  loadPlugin(path: string, callback: (...args: any[]) => any) {
+  loadPlugin(path: string, callback?: NodeJSLikeCallback<any>) {
     return readFile(path).then(script => {
       // Based on: https://github.com/joyent/node/blob/v0.10.33/src/node.js#L516
       const module = new Module(path);
       module.filename = path;
       module.paths = Module._nodeModulePaths(path);
 
-      function req(path) {
+      function req(path: string) {
         return module.require(path);
       }
 
-      req.resolve = request => Module._resolveFilename(request, module);
+      req.resolve = (request: string) => Module._resolveFilename(request, module);
 
       req.main = require.main;
       req.extensions = Module._extensions;
@@ -400,7 +401,7 @@ class Hexo extends EventEmitter {
     return args.draft || args.drafts || this.config.render_drafts;
   }
 
-  load(callback) {
+  load(callback?: NodeJSLikeCallback<any>) {
     return loadDatabase(this).then(() => {
       this.log.info('Start processing');
 
@@ -414,7 +415,7 @@ class Hexo extends EventEmitter {
     }).asCallback(callback);
   }
 
-  watch(callback) {
+  watch(callback?: NodeJSLikeCallback<any>) {
     let useCache = false;
     const { cache } = Object.assign({
       cache: false
@@ -478,7 +479,7 @@ class Hexo extends EventEmitter {
       site: object;
       cache?: boolean;
 
-      constructor(path, locals) {
+      constructor(path: string, locals) {
         this.page = { ...locals };
         if (this.page.path == null) this.page.path = path;
         this.path = path;
@@ -512,7 +513,7 @@ class Hexo extends EventEmitter {
     }, []);
   }
 
-  _routerRefresh(runningGenerators, useCache) {
+  _routerRefresh(runningGenerators: Promise<any[]>, useCache: boolean) {
     const { route } = this;
     const routeList = route.list();
     const Locals = this._generateLocals();
@@ -580,11 +581,11 @@ class Hexo extends EventEmitter {
     });
   }
 
-  execFilter(type, data, options) {
+  execFilter(type: string, data: any, options) {
     return this.extend.filter.exec(type, data, options);
   }
 
-  execFilterSync(type, data, options) {
+  execFilterSync(type: string, data: any, options) {
     return this.extend.filter.execSync(type, data, options);
   }
 }
diff --git a/lib/hexo/load_config.ts b/lib/hexo/load_config.ts
index 231e285f02..489f4e03ff 100644
--- a/lib/hexo/load_config.ts
+++ b/lib/hexo/load_config.ts
@@ -6,8 +6,9 @@ import { exists, readdir } from 'hexo-fs';
 import { magenta } from 'picocolors';
 import { deepMerge } from 'hexo-util';
 import validateConfig from './validate_config';
+import type Hexo from './index';
 
-export = async ctx => {
+export = async (ctx: Hexo) => {
   if (!ctx.env.init) return;
 
   const baseDir = ctx.base_dir;
@@ -65,7 +66,7 @@ export = async ctx => {
 
 };
 
-async function findConfigPath(path) {
+async function findConfigPath(path: string) {
   const { dir, name } = parse(path);
 
   const files = await readdir(dir);
diff --git a/lib/hexo/load_database.ts b/lib/hexo/load_database.ts
index c64719c929..f0ac5decb0 100644
--- a/lib/hexo/load_database.ts
+++ b/lib/hexo/load_database.ts
@@ -1,7 +1,8 @@
 import { exists, unlink } from 'hexo-fs';
 import Promise from 'bluebird';
+import type Hexo from './index';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   if (ctx._dbLoaded) return Promise.resolve();
 
   const db = ctx.database;
diff --git a/lib/hexo/load_plugins.ts b/lib/hexo/load_plugins.ts
index c1dcb29067..289474f00f 100644
--- a/lib/hexo/load_plugins.ts
+++ b/lib/hexo/load_plugins.ts
@@ -2,14 +2,15 @@ import { join } from 'path';
 import { exists, readFile, listDir } from 'hexo-fs';
 import Promise from 'bluebird';
 import { magenta } from 'picocolors';
+import type Hexo from './index';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   if (!ctx.env.init || ctx.env.safe) return;
 
   return loadModules(ctx).then(() => loadScripts(ctx));
 };
 
-function loadModuleList(ctx, basedir) {
+function loadModuleList(ctx: Hexo, basedir: string) {
   const packagePath = join(basedir, 'package.json');
 
   // Make sure package.json exists
@@ -42,14 +43,14 @@ function loadModuleList(ctx, basedir) {
   });
 }
 
-function loadModules(ctx) {
+function loadModules(ctx: Hexo) {
   return Promise.map([ctx.base_dir, ctx.theme_dir], basedir => loadModuleList(ctx, basedir))
     .then(([hexoModuleList, themeModuleList]) => {
       return Object.entries(Object.assign(themeModuleList, hexoModuleList));
     })
     .map(([name, path]) => {
       // Load plugins
-      return ctx.loadPlugin(path).then(() => {
+      return ctx.loadPlugin(path as string).then(() => {
         ctx.log.debug('Plugin loaded: %s', magenta(name));
       }).catch(err => {
         ctx.log.error({err}, 'Plugin load failed: %s', magenta(name));
@@ -57,7 +58,7 @@ function loadModules(ctx) {
     });
 }
 
-function loadScripts(ctx) {
+function loadScripts(ctx: Hexo) {
   const baseDirLength = ctx.base_dir.length;
 
   return Promise.filter([
@@ -76,6 +77,6 @@ function loadScripts(ctx) {
   }));
 }
 
-function displayPath(path, baseDirLength) {
+function displayPath(path: string, baseDirLength: number) {
   return magenta(path.substring(baseDirLength));
 }
diff --git a/lib/hexo/load_theme_config.ts b/lib/hexo/load_theme_config.ts
index 57a28adb41..54c700960a 100644
--- a/lib/hexo/load_theme_config.ts
+++ b/lib/hexo/load_theme_config.ts
@@ -3,8 +3,9 @@ import tildify from 'tildify';
 import { exists, readdir } from 'hexo-fs';
 import { magenta } from 'picocolors';
 import { deepMerge } from 'hexo-util';
+import type Hexo from './index';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   if (!ctx.env.init) return;
   if (!ctx.config.theme) return;
 
@@ -30,7 +31,7 @@ export = ctx => {
   });
 };
 
-function findConfigPath(path) {
+function findConfigPath(path: string) {
   const { dir, name } = parse(path);
 
   return readdir(dir).then(files => {
diff --git a/lib/hexo/locals.ts b/lib/hexo/locals.ts
index 468dabe26f..7153cb0a48 100644
--- a/lib/hexo/locals.ts
+++ b/lib/hexo/locals.ts
@@ -9,7 +9,7 @@ class Locals {
     this.getters = {};
   }
 
-  get(name) {
+  get(name: string) {
     if (typeof name !== 'string') throw new TypeError('name must be a string!');
 
     return this.cache.apply(name, () => {
@@ -20,7 +20,7 @@ class Locals {
     });
   }
 
-  set(name, value) {
+  set(name: string, value: any) {
     if (typeof name !== 'string') throw new TypeError('name must be a string!');
     if (value == null) throw new TypeError('value is required!');
 
@@ -32,7 +32,7 @@ class Locals {
     return this;
   }
 
-  remove(name) {
+  remove(name: string) {
     if (typeof name !== 'string') throw new TypeError('name must be a string!');
 
     this.getters[name] = null;
diff --git a/lib/hexo/multi_config_path.ts b/lib/hexo/multi_config_path.ts
index 8d140d3569..978c04fca0 100644
--- a/lib/hexo/multi_config_path.ts
+++ b/lib/hexo/multi_config_path.ts
@@ -2,8 +2,9 @@ import { isAbsolute, resolve, join, extname } from 'path';
 import { existsSync, readFileSync, writeFileSync } from 'hexo-fs';
 import yml from 'js-yaml';
 import { deepMerge } from 'hexo-util';
+import type Hexo from './index';
 
-export = ctx => function multiConfigPath(base, configPaths, outputDir) {
+export = (ctx: Hexo) => function multiConfigPath(base: string, configPaths: string, outputDir: string) {
   const { log } = ctx;
   const defaultPath = join(base, '_config.yml');
 
@@ -12,7 +13,7 @@ export = ctx => function multiConfigPath(base, configPaths, outputDir) {
     return join(base, '_config.yml');
   }
 
-  let paths;
+  let paths: string[];
   // determine if comma or space separated
   if (configPaths.includes(',')) {
     paths = configPaths.replace(' ', '').split(',');
diff --git a/lib/hexo/post.ts b/lib/hexo/post.ts
index 748d73fd94..f9269484e2 100644
--- a/lib/hexo/post.ts
+++ b/lib/hexo/post.ts
@@ -7,6 +7,7 @@ import { load } from 'js-yaml';
 import { slugize, escapeRegExp } from 'hexo-util';
 import { copyDir, exists, listDir, mkdirs, readFile, rmdir, unlink, writeFile } from 'hexo-fs';
 import { parse as yfmParse, split as yfmSplit, stringify as yfmStringify } from 'hexo-front-matter';
+import type Hexo from './index';
 const preservedKeys = ['title', 'slug', 'path', 'layout', 'date', 'content'];
 
 const rHexoPostRenderEscape = /<hexoPostRenderCodeBlock>([\s\S]+?)<\/hexoPostRenderCodeBlock>/g;
@@ -20,7 +21,7 @@ const STATE_SWIG_COMMENT = Symbol('swig_comment');
 const STATE_SWIG_TAG = Symbol('swig_tag');
 const STATE_SWIG_FULL_TAG = Symbol('swig_full_tag');
 
-const isNonWhiteSpaceChar = char => char !== '\r'
+const isNonWhiteSpaceChar = (char: string) => char !== '\r'
   && char !== '\n'
   && char !== '\t'
   && char !== '\f'
@@ -28,18 +29,18 @@ const isNonWhiteSpaceChar = char => char !== '\r'
   && char !== ' ';
 
 class PostRenderEscape {
-  public stored: any;
-  public length: any;
+  public stored: any[];
+  public length: number;
 
   constructor() {
     this.stored = [];
   }
 
-  static escapeContent(cache, flag, str) {
+  static escapeContent(cache: any[], flag: string, str: string) {
     return `<!--${flag}\uFFFC${cache.push(str) - 1}-->`;
   }
 
-  static restoreContent(cache) {
+  static restoreContent(cache: any[]) {
     return (_, index) => {
       assert(cache[index]);
       const value = cache[index];
@@ -48,16 +49,16 @@ class PostRenderEscape {
     };
   }
 
-  restoreAllSwigTags(str) {
+  restoreAllSwigTags(str: string) {
     const restored = str.replace(rSwigPlaceHolder, PostRenderEscape.restoreContent(this.stored));
     return restored;
   }
 
-  restoreCodeBlocks(str) {
+  restoreCodeBlocks(str: string) {
     return str.replace(rCodeBlockPlaceHolder, PostRenderEscape.restoreContent(this.stored));
   }
 
-  escapeCodeBlocks(str) {
+  escapeCodeBlocks(str: string) {
     return str.replace(rHexoPostRenderEscape, (_, content) => PostRenderEscape.escapeContent(this.stored, 'code', content));
   }
 
@@ -65,7 +66,7 @@ class PostRenderEscape {
    * @param {string} str
    * @returns string
    */
-  escapeAllSwigTags(str) {
+  escapeAllSwigTags(str: string) {
     let state = STATE_PLAINTEXT;
     let buffer = '';
     let output = '';
@@ -185,7 +186,7 @@ class PostRenderEscape {
   }
 }
 
-const prepareFrontMatter = (data, jsonMode) => {
+const prepareFrontMatter = (data: any, jsonMode: boolean) => {
   for (const [key, item] of Object.entries(data)) {
     if (moment.isMoment(item)) {
       data[key] = item.utc().format('YYYY-MM-DD HH:mm:ss');
@@ -202,11 +203,11 @@ const prepareFrontMatter = (data, jsonMode) => {
 };
 
 
-const removeExtname = str => {
+const removeExtname = (str: string) => {
   return str.substring(0, str.length - extname(str).length);
 };
 
-const createAssetFolder = (path, assetFolder) => {
+const createAssetFolder = (path: string, assetFolder: boolean) => {
   if (!assetFolder) return Promise.resolve();
 
   const target = removeExtname(path);
@@ -231,17 +232,24 @@ interface Data {
   source?: string;
 }
 
+interface PostData {
+  title?: string;
+  layout?: string;
+  slug?: string;
+  path?: string;
+  [prop: string]: any;
+}
+
 class Post {
-  public context: any;
-  public config: any;
-  public tag: any;
-  public separator: any;
+  public context: Hexo;
 
-  constructor(context) {
+  constructor(context: Hexo) {
     this.context = context;
   }
 
-  create(data, replace, callback?) {
+  create(data: PostData, callback?: NodeJSLikeCallback<any>);
+  create(data: PostData, replace: boolean, callback?: NodeJSLikeCallback<any>);
+  create(data: PostData, replace: boolean | (NodeJSLikeCallback<any>), callback?: NodeJSLikeCallback<any>) {
     if (!callback && typeof replace === 'function') {
       callback = replace;
       replace = false;
@@ -276,7 +284,7 @@ class Post {
     }).asCallback(callback);
   }
 
-  _getScaffold(layout) {
+  _getScaffold(layout: string) {
     const ctx = this.context;
 
     return ctx.scaffold.get(layout).then(result => {
@@ -285,7 +293,7 @@ class Post {
     });
   }
 
-  _renderScaffold(data) {
+  _renderScaffold(data: PostData) {
     const { tag } = this.context.extend;
     let splitted;
 
@@ -327,7 +335,7 @@ class Post {
     });
   }
 
-  publish(data, replace, callback) {
+  publish(data: PostData, replace: boolean, callback?: NodeJSLikeCallback<Result>) {
     if (!callback && typeof replace === 'function') {
       callback = replace;
       replace = false;
@@ -354,7 +362,7 @@ class Post {
       // Read the content
       src = join(draftDir, item);
       return readFile(src);
-    }).then(content => {
+    }).then((content: string) => {
       // Create post
       Object.assign(data, yfmParse(content));
       data.content = data._content;
@@ -380,7 +388,7 @@ class Post {
     }).thenReturn(result).asCallback(callback);
   }
 
-  render(source, data: Data = {}, callback) {
+  render(source: string, data: Data = {}, callback?: NodeJSLikeCallback<never>) {
     const ctx = this.context;
     const { config } = ctx;
     const { tag } = ctx.extend;
diff --git a/lib/hexo/register_models.ts b/lib/hexo/register_models.ts
index 864e4e3631..88a73e6081 100644
--- a/lib/hexo/register_models.ts
+++ b/lib/hexo/register_models.ts
@@ -1,6 +1,7 @@
 import * as models from '../models';
+import type Hexo from './index';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const db = ctx.database;
 
   const keys = Object.keys(models);
diff --git a/lib/hexo/render.ts b/lib/hexo/render.ts
index a25d152314..4d1ebda922 100644
--- a/lib/hexo/render.ts
+++ b/lib/hexo/render.ts
@@ -1,8 +1,11 @@
 import { extname } from 'path';
 import Promise from 'bluebird';
 import { readFile, readFileSync } from 'hexo-fs';
+import type Hexo from './index';
+import type { Renderer } from '../extend';
+import type { StoreFunctionData } from '../extend/renderer';
 
-const getExtname = str => {
+const getExtname = (str: string) => {
   if (typeof str !== 'string') return '';
 
   const ext = extname(str);
@@ -24,35 +27,35 @@ const toString = (result, options) => {
 };
 
 class Render {
-  public context: any;
-  public renderer: any;
+  public context: Hexo;
+  public renderer: Renderer;
 
-  constructor(ctx) {
+  constructor(ctx: Hexo) {
     this.context = ctx;
     this.renderer = ctx.extend.renderer;
   }
 
-  isRenderable(path) {
+  isRenderable(path: string) {
     return this.renderer.isRenderable(path);
   }
 
-  isRenderableSync(path) {
+  isRenderableSync(path: string) {
     return this.renderer.isRenderableSync(path);
   }
 
-  getOutput(path) {
+  getOutput(path: string) {
     return this.renderer.getOutput(path);
   }
 
-  getRenderer(ext, sync?) {
+  getRenderer(ext: string, sync?: boolean) {
     return this.renderer.get(ext, sync);
   }
 
-  getRendererSync(ext) {
+  getRendererSync(ext: string) {
     return this.getRenderer(ext, true);
   }
 
-  render(data, options, callback) {
+  render(data: StoreFunctionData, options?: { highlight?: boolean; }, callback?: undefined) {
     if (!callback && typeof options === 'function') {
       callback = options;
       options = {};
@@ -96,14 +99,14 @@ class Render {
     }).asCallback(callback);
   }
 
-  renderSync(data, options = {}) {
+  renderSync(data: StoreFunctionData, options = {}) {
     if (!data) throw new TypeError('No input file or string!');
 
     const ctx = this.context;
 
     if (data.text == null) {
       if (!data.path) throw new TypeError('No input file or string!');
-      data.text = readFileSync(data.path);
+      data.text = readFileSync(data.path) as string;
     }
 
     if (data.text == null) throw new TypeError('No input file or string!');
diff --git a/lib/hexo/router.ts b/lib/hexo/router.ts
index f00824d381..33edb61478 100644
--- a/lib/hexo/router.ts
+++ b/lib/hexo/router.ts
@@ -18,8 +18,6 @@ class RouteStream extends Readable {
   public _data: any;
   public _ended: boolean;
   public modified: any;
-  public push: any;
-  public emit: any;
 
   constructor(data: Data) {
     super({ objectMode: true });
@@ -133,14 +131,14 @@ class Router extends EventEmitter {
     return new RouteStream(data);
   }
 
-  isModified(path) {
+  isModified(path: string) {
     if (typeof path !== 'string') throw new TypeError('path must be a string!');
 
     const data = this.routes[this.format(path)];
     return data ? data.modified : false;
   }
 
-  set(path, data) {
+  set(path: string, data: any) {
     if (typeof path !== 'string') throw new TypeError('path must be a string!');
     if (data == null) throw new TypeError('data is required!');
 
@@ -175,7 +173,7 @@ class Router extends EventEmitter {
     return this;
   }
 
-  remove(path) {
+  remove(path: string) {
     if (typeof path !== 'string') throw new TypeError('path must be a string!');
     path = this.format(path);
 
diff --git a/lib/hexo/scaffold.ts b/lib/hexo/scaffold.ts
index 18a1a5ff41..37b6e65e86 100644
--- a/lib/hexo/scaffold.ts
+++ b/lib/hexo/scaffold.ts
@@ -1,12 +1,12 @@
 import { extname, join } from 'path';
 import { exists, listDir, readFile, unlink, writeFile } from 'hexo-fs';
-
+import type Hexo from './index';
 class Scaffold {
-  public context: any;
-  public scaffoldDir: any;
+  public context: Hexo;
+  public scaffoldDir: string;
   public defaults: any;
 
-  constructor(context) {
+  constructor(context: Hexo) {
     this.context = context;
     this.scaffoldDir = context.scaffold_dir;
     this.defaults = {
@@ -36,11 +36,11 @@ class Scaffold {
     }));
   }
 
-  _getScaffold(name) {
+  _getScaffold(name: string) {
     return this._listDir().then(list => list.find(item => item.name === name));
   }
 
-  get(name, callback) {
+  get(name: string, callback?: NodeJSLikeCallback<any>) {
     return this._getScaffold(name).then(item => {
       if (item) {
         return readFile(item.path);
@@ -50,7 +50,7 @@ class Scaffold {
     }).asCallback(callback);
   }
 
-  set(name, content, callback) {
+  set(name: string, content: any, callback: NodeJSLikeCallback<void>) {
     const { scaffoldDir } = this;
 
     return this._getScaffold(name).then(item => {
@@ -61,7 +61,7 @@ class Scaffold {
     }).asCallback(callback);
   }
 
-  remove(name, callback) {
+  remove(name: string, callback: NodeJSLikeCallback<void>) {
     return this._getScaffold(name).then(item => {
       if (!item) return;
 
diff --git a/lib/hexo/source.ts b/lib/hexo/source.ts
index ab4d26bc45..736a41037f 100644
--- a/lib/hexo/source.ts
+++ b/lib/hexo/source.ts
@@ -1,7 +1,8 @@
 import Box from '../box';
+import type Hexo from './index';
 
 class Source extends Box {
-  constructor(ctx) {
+  constructor(ctx: Hexo) {
     super(ctx, ctx.source_dir);
 
     this.processors = ctx.extend.processor.list();
diff --git a/lib/hexo/update_package.ts b/lib/hexo/update_package.ts
index 03319913e6..4b8f3593bd 100644
--- a/lib/hexo/update_package.ts
+++ b/lib/hexo/update_package.ts
@@ -1,7 +1,8 @@
 import { join } from 'path';
 import { writeFile, exists, readFile } from 'hexo-fs';
+import type Hexo from './index';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const pkgPath = join(ctx.base_dir, 'package.json');
 
   return readPkg(pkgPath).then(pkg => {
@@ -18,7 +19,7 @@ export = ctx => {
   });
 };
 
-function readPkg(path) {
+function readPkg(path: string) {
   return exists(path).then(exist => {
     if (!exist) return;
 
diff --git a/lib/hexo/validate_config.ts b/lib/hexo/validate_config.ts
index 8dfcb389e9..66af8ceeba 100644
--- a/lib/hexo/validate_config.ts
+++ b/lib/hexo/validate_config.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from './index';
+
+export = (ctx: Hexo) => {
   const { config, log } = ctx;
 
   log.info('Validating config');
diff --git a/lib/models/asset.ts b/lib/models/asset.ts
index 006391d3b5..5a761192da 100644
--- a/lib/models/asset.ts
+++ b/lib/models/asset.ts
@@ -1,7 +1,8 @@
 import warehouse from 'warehouse';
 import { join } from 'path';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Asset = new warehouse.Schema({
     _id: {type: String, required: true},
     path: {type: String, required: true},
diff --git a/lib/models/cache.ts b/lib/models/cache.ts
index d4b43f4722..60db5ce1c4 100644
--- a/lib/models/cache.ts
+++ b/lib/models/cache.ts
@@ -1,7 +1,8 @@
 import warehouse from 'warehouse';
 import Promise from 'bluebird';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Cache = new warehouse.Schema({
     _id: {type: String, required: true},
     hash: {type: String, default: ''},
diff --git a/lib/models/category.ts b/lib/models/category.ts
index 740bc67015..2fdbfb58df 100644
--- a/lib/models/category.ts
+++ b/lib/models/category.ts
@@ -1,7 +1,8 @@
 import warehouse from 'warehouse';
 import { slugize, full_url_for } from 'hexo-util';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Category = new warehouse.Schema({
     name: {type: String, required: true},
     parent: { type: warehouse.Schema.Types.CUID, ref: 'Category'}
diff --git a/lib/models/data.ts b/lib/models/data.ts
index 0cdefe318a..89832d3cf0 100644
--- a/lib/models/data.ts
+++ b/lib/models/data.ts
@@ -1,6 +1,7 @@
 import warehouse from 'warehouse';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Data = new warehouse.Schema({
     _id: {type: String, required: true},
     data: Object
diff --git a/lib/models/page.ts b/lib/models/page.ts
index bbaa606422..f1a96922d7 100644
--- a/lib/models/page.ts
+++ b/lib/models/page.ts
@@ -3,8 +3,9 @@ import { join } from 'path';
 import Moment from './types/moment';
 import moment from 'moment';
 import { full_url_for } from 'hexo-util';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Page = new warehouse.Schema({
     title: {type: String, default: ''},
     date: {
diff --git a/lib/models/post.ts b/lib/models/post.ts
index 10b274d7ad..208e8ea477 100644
--- a/lib/models/post.ts
+++ b/lib/models/post.ts
@@ -4,6 +4,7 @@ import { extname, join, sep } from 'path';
 import Promise from 'bluebird';
 import Moment from './types/moment';
 import { full_url_for, Cache } from 'hexo-util';
+import type Hexo from '../hexo';
 
 function pickID(data) {
   return data._id;
@@ -15,7 +16,7 @@ function removeEmptyTag(tags) {
 
 const tagsGetterCache = new Cache();
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Post = new warehouse.Schema({
     id: String,
     title: {type: String, default: ''},
diff --git a/lib/models/post_asset.ts b/lib/models/post_asset.ts
index 72ec5f90f1..fe73a02a47 100644
--- a/lib/models/post_asset.ts
+++ b/lib/models/post_asset.ts
@@ -1,7 +1,8 @@
 import warehouse from 'warehouse';
 import { join } from 'path';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const PostAsset = new warehouse.Schema({
     _id: {type: String, required: true},
     slug: {type: String, required: true},
diff --git a/lib/models/post_category.ts b/lib/models/post_category.ts
index f3c813f8be..8b8feb0c0a 100644
--- a/lib/models/post_category.ts
+++ b/lib/models/post_category.ts
@@ -1,6 +1,7 @@
 import warehouse from 'warehouse';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const PostCategory = new warehouse.Schema({
     post_id: {type: warehouse.Schema.Types.CUID, ref: 'Post'},
     category_id: {type: warehouse.Schema.Types.CUID, ref: 'Category'}
diff --git a/lib/models/post_tag.ts b/lib/models/post_tag.ts
index e727ca5e3e..b55533c49a 100644
--- a/lib/models/post_tag.ts
+++ b/lib/models/post_tag.ts
@@ -1,6 +1,7 @@
 import warehouse from 'warehouse';
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const PostTag = new warehouse.Schema({
     post_id: {type: warehouse.Schema.Types.CUID, ref: 'Post'},
     tag_id: {type: warehouse.Schema.Types.CUID, ref: 'Tag'}
diff --git a/lib/models/tag.ts b/lib/models/tag.ts
index 9c5b10a55e..84a118aa25 100644
--- a/lib/models/tag.ts
+++ b/lib/models/tag.ts
@@ -1,8 +1,9 @@
 import warehouse from 'warehouse';
 import { slugize, full_url_for } from 'hexo-util';
 const { hasOwnProperty: hasOwn } = Object.prototype;
+import type Hexo from '../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const Tag = new warehouse.Schema({
     name: {type: String, required: true}
   });
diff --git a/lib/plugins/console/clean.ts b/lib/plugins/console/clean.ts
index fb799039d8..eea456a757 100644
--- a/lib/plugins/console/clean.ts
+++ b/lib/plugins/console/clean.ts
@@ -1,7 +1,8 @@
 import Promise from 'bluebird';
 import { exists, unlink, rmdir } from 'hexo-fs';
+import type Hexo from '../../hexo';
 
-function cleanConsole(args) {
+function cleanConsole(this: Hexo): Promise<[void, void, any]> {
   return Promise.all([
     deleteDatabase(this),
     deletePublicDir(this),
@@ -9,7 +10,7 @@ function cleanConsole(args) {
   ]);
 }
 
-function deleteDatabase(ctx) {
+function deleteDatabase(ctx: Hexo): Promise<void> {
   const dbPath = ctx.database.options.path;
 
   return exists(dbPath).then(exist => {
@@ -21,7 +22,7 @@ function deleteDatabase(ctx) {
   });
 }
 
-function deletePublicDir(ctx) {
+function deletePublicDir(ctx: Hexo): Promise<void> {
   const publicDir = ctx.public_dir;
 
   return exists(publicDir).then(exist => {
diff --git a/lib/plugins/console/config.ts b/lib/plugins/console/config.ts
index 841c241c23..777bc4e1d0 100644
--- a/lib/plugins/console/config.ts
+++ b/lib/plugins/console/config.ts
@@ -2,8 +2,9 @@ import yaml from 'js-yaml';
 import { exists, writeFile } from 'hexo-fs';
 import { extname } from 'path';
 import Promise from 'bluebird';
+import type Hexo from '../../hexo';
 
-function configConsole(args) {
+function configConsole(this: Hexo, args): Promise<void> {
   const key = args._[0];
   let value = args._[1];
 
@@ -35,7 +36,7 @@ function configConsole(args) {
   });
 }
 
-function getProperty(obj, key) {
+function getProperty(obj: object, key: string): any {
   const split = key.split('.');
   let result = obj[split[0]];
 
@@ -46,7 +47,7 @@ function getProperty(obj, key) {
   return result;
 }
 
-function setProperty(obj, key, value) {
+function setProperty(obj: object, key: string, value: any): void {
   const split = key.split('.');
   let cursor = obj;
   const lastKey = split.pop();
@@ -60,7 +61,7 @@ function setProperty(obj, key, value) {
   cursor[lastKey] = value;
 }
 
-function castValue(value) {
+function castValue(value: string): any {
   switch (value) {
     case 'true':
       return true;
diff --git a/lib/plugins/console/deploy.ts b/lib/plugins/console/deploy.ts
index 6da32c2e76..1da54819d4 100644
--- a/lib/plugins/console/deploy.ts
+++ b/lib/plugins/console/deploy.ts
@@ -1,7 +1,8 @@
 import { exists } from 'hexo-fs';
 import { underline, magenta } from 'picocolors';
+import type Hexo from '../../hexo';
 
-function deployConsole(args) {
+function deployConsole(this: Hexo, args) {
   let config = this.config.deploy;
   const deployers = this.extend.deployer.list();
 
diff --git a/lib/plugins/console/generate.ts b/lib/plugins/console/generate.ts
index ccae2b3d94..2b17697b49 100644
--- a/lib/plugins/console/generate.ts
+++ b/lib/plugins/console/generate.ts
@@ -6,21 +6,22 @@ import { cyan, magenta } from 'picocolors';
 import tildify from 'tildify';
 import { PassThrough } from 'stream';
 import { createSha1Hash } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 class Generater {
-  public context: any;
+  public context: Hexo;
   public force: any;
   public bail: any;
   public concurrency: any;
   public watch: any;
   public deploy: any;
-  public generatingFiles: any;
-  public start: any;
+  public generatingFiles: Set<any>;
+  public start: [number, number];
   public args: any;
   public route: any;
   public log: any;
 
-  constructor(ctx, args) {
+  constructor(ctx: Hexo, args) {
     this.context = ctx;
     this.force = args.f || args.force;
     this.bail = args.b || args.bail;
@@ -31,7 +32,7 @@ class Generater {
     this.start = process.hrtime();
     this.args = args;
   }
-  generateFile(path) {
+  generateFile(path: string) {
     const publicDir = this.context.public_dir;
     const { generatingFiles } = this;
     const { route } = this.context;
@@ -58,7 +59,7 @@ class Generater {
       generatingFiles.delete(path);
     });
   }
-  writeFile(path, force?) {
+  writeFile(path: string, force?: boolean): Promise<any> {
     const { route, log } = this.context;
     const publicDir = this.context.public_dir;
     const Cache = this.context.model('Cache');
@@ -99,7 +100,7 @@ class Generater {
       });
     });
   }
-  deleteFile(path) {
+  deleteFile(path: string): Promise<void> {
     const { log } = this.context;
     const publicDir = this.context.public_dir;
     const dest = join(publicDir, path);
@@ -126,7 +127,7 @@ class Generater {
 
     return dataStream.pipe(new PassThrough());
   }
-  firstGenerate() {
+  firstGenerate(): Promise<void> {
     const { concurrency } = this;
     const { route, log } = this.context;
     const publicDir = this.context.public_dir;
@@ -171,7 +172,7 @@ class Generater {
       log.info('%d files generated in %s', count, cyan(interval));
     });
   }
-  execWatch() {
+  execWatch(): Promise<void> {
     const { route, log } = this.context;
     return this.context.watch().then(() => this.firstGenerate()).then(() => {
       log.info('Hexo is watching for file changes. Press Ctrl+C to exit.');
diff --git a/lib/plugins/console/list/category.ts b/lib/plugins/console/list/category.ts
index 0044ec3a0e..a1c6527c80 100644
--- a/lib/plugins/console/list/category.ts
+++ b/lib/plugins/console/list/category.ts
@@ -1,8 +1,9 @@
 import { underline } from 'picocolors';
 import table from 'text-table';
 import { stringLength } from './common';
+import type Hexo from '../../../hexo';
 
-function listCategory() {
+function listCategory(this: Hexo): void {
   const categories = this.model('Category');
 
   const data = categories.sort({name: 1}).map(cate => [cate.name, String(cate.length)]);
diff --git a/lib/plugins/console/list/common.ts b/lib/plugins/console/list/common.ts
index 5adcb8022c..cc18685f5c 100644
--- a/lib/plugins/console/list/common.ts
+++ b/lib/plugins/console/list/common.ts
@@ -1,6 +1,6 @@
 import strip from 'strip-ansi';
 
-export function stringLength(str) {
+export function stringLength(str: string): number {
   str = strip(str);
 
   const len = str.length;
diff --git a/lib/plugins/console/list/index.ts b/lib/plugins/console/list/index.ts
index 7c3f084138..cd091ca272 100644
--- a/lib/plugins/console/list/index.ts
+++ b/lib/plugins/console/list/index.ts
@@ -4,6 +4,7 @@ import post from './post';
 import route from './route';
 import tag from './tag';
 import category from './category';
+import type Hexo from '../../../hexo';
 
 const store = {
   page, post, route, tag, category
@@ -11,7 +12,7 @@ const store = {
 
 const alias = abbrev(Object.keys(store));
 
-function listConsole(args) {
+function listConsole(this: Hexo, args) {
   const type = args._.shift();
 
   // Display help message if user didn't input any arguments
diff --git a/lib/plugins/console/list/page.ts b/lib/plugins/console/list/page.ts
index d132231450..8b9de1bc09 100644
--- a/lib/plugins/console/list/page.ts
+++ b/lib/plugins/console/list/page.ts
@@ -1,8 +1,9 @@
 import { magenta, underline, gray } from 'picocolors';
 import table from 'text-table';
 import { stringLength } from './common';
+import type Hexo from '../../../hexo';
 
-function listPage() {
+function listPage(this: Hexo): void {
   const Page = this.model('Page');
 
   const data = Page.sort({date: 1}).map(page => {
diff --git a/lib/plugins/console/list/post.ts b/lib/plugins/console/list/post.ts
index e4dca1a578..280b339df8 100644
--- a/lib/plugins/console/list/post.ts
+++ b/lib/plugins/console/list/post.ts
@@ -1,12 +1,13 @@
 import { gray, magenta, underline } from 'picocolors';
 import table from 'text-table';
 import { stringLength } from './common';
+import type Hexo from '../../../hexo';
 
 function mapName(item) {
   return item.name;
 }
 
-function listPost() {
+function listPost(this: Hexo): void {
   const Post = this.model('Post');
 
   const data = Post.sort({published: -1, date: 1}).map(post => {
diff --git a/lib/plugins/console/list/route.ts b/lib/plugins/console/list/route.ts
index a29e4e4c54..2c15e217cc 100644
--- a/lib/plugins/console/list/route.ts
+++ b/lib/plugins/console/list/route.ts
@@ -1,6 +1,7 @@
 import archy from 'archy';
+import type Hexo from '../../../hexo';
 
-function listRoute() {
+function listRoute(this: Hexo): void {
   const routes = this.route.list().sort();
   const tree = buildTree(routes);
   const nodes = buildNodes(tree);
diff --git a/lib/plugins/console/list/tag.ts b/lib/plugins/console/list/tag.ts
index 09c0a148df..4ce37595d1 100644
--- a/lib/plugins/console/list/tag.ts
+++ b/lib/plugins/console/list/tag.ts
@@ -1,8 +1,9 @@
 import { magenta, underline } from 'picocolors';
 import table from 'text-table';
 import { stringLength } from './common';
+import type Hexo from '../../../hexo';
 
-function listTag() {
+function listTag(this: Hexo): void {
   const Tag = this.model('Tag');
 
   const data = Tag.sort({name: 1}).map(tag => [tag.name, String(tag.length), magenta(tag.path)]);
diff --git a/lib/plugins/console/migrate.ts b/lib/plugins/console/migrate.ts
index df341f6ed4..afe5dfb537 100644
--- a/lib/plugins/console/migrate.ts
+++ b/lib/plugins/console/migrate.ts
@@ -1,6 +1,7 @@
 import { underline, magenta } from 'picocolors';
+import type Hexo from '../../hexo';
 
-function migrateConsole(args) {
+function migrateConsole(this: Hexo, args) {
   // Display help message if user didn't input any arguments
   if (!args._.length) {
     return this.call('help', {_: ['migrate']});
diff --git a/lib/plugins/console/new.ts b/lib/plugins/console/new.ts
index becbe1c625..64e3d83bd1 100644
--- a/lib/plugins/console/new.ts
+++ b/lib/plugins/console/new.ts
@@ -1,6 +1,7 @@
 import tildify from 'tildify';
 import { magenta } from 'picocolors';
 import { basename } from 'path';
+import Hexo from '../../hexo';
 
 const reservedKeys = {
   _: true,
@@ -19,7 +20,7 @@ const reservedKeys = {
   silent: true
 };
 
-function newConsole(args) {
+function newConsole(this: Hexo, args) {
   const path = args.p || args.path;
   let title;
   if (args._.length) {
diff --git a/lib/plugins/console/publish.ts b/lib/plugins/console/publish.ts
index f73d87ec55..6f97f9d175 100644
--- a/lib/plugins/console/publish.ts
+++ b/lib/plugins/console/publish.ts
@@ -1,7 +1,8 @@
 import tildify from 'tildify';
 import { magenta } from 'picocolors';
+import type Hexo from '../../hexo';
 
-function publishConsole(args) {
+function publishConsole(this: Hexo, args) {
   // Display help message if user didn't input any arguments
   if (!args._.length) {
     return this.call('help', {_: ['publish']});
diff --git a/lib/plugins/console/render.ts b/lib/plugins/console/render.ts
index 01cb57c581..c40230f728 100644
--- a/lib/plugins/console/render.ts
+++ b/lib/plugins/console/render.ts
@@ -3,8 +3,9 @@ import tildify from 'tildify';
 import prettyHrtime from 'pretty-hrtime';
 import { writeFile } from 'hexo-fs';
 import { cyan, magenta } from 'picocolors';
+import type Hexo from '../../hexo';
 
-function renderConsole(args) {
+function renderConsole(this: Hexo, args) {
   // Display help message if user didn't input any arguments
   if (!args._.length) {
     return this.call('help', {_: 'render'});
diff --git a/lib/plugins/filter/after_post_render/excerpt.ts b/lib/plugins/filter/after_post_render/excerpt.ts
index ef1746a352..5694ce5dec 100644
--- a/lib/plugins/filter/after_post_render/excerpt.ts
+++ b/lib/plugins/filter/after_post_render/excerpt.ts
@@ -1,6 +1,6 @@
 const rExcerpt = /<!-- ?more ?-->/i;
 
-function excerptFilter(data) {
+function excerptFilter(data): void {
   const { content } = data;
 
   if (typeof data.excerpt !== 'undefined') {
diff --git a/lib/plugins/filter/after_post_render/external_link.ts b/lib/plugins/filter/after_post_render/external_link.ts
index 0b116de8b4..dab35b3a9d 100644
--- a/lib/plugins/filter/after_post_render/external_link.ts
+++ b/lib/plugins/filter/after_post_render/external_link.ts
@@ -1,11 +1,12 @@
 import { isExternalLink } from 'hexo-util';
+import type Hexo from '../../../hexo';
 let EXTERNAL_LINK_POST_ENABLED = true;
 const rATag = /<a(?:\s+?|\s+?[^<>]+?\s+?)href=["']((?:https?:|\/\/)[^<>"']+)["'][^<>]*>/gi;
 const rTargetAttr = /target=/i;
 const rRelAttr = /rel=/i;
 const rRelStrAttr = /rel=["']([^<>"']*)["']/i;
 
-function externalLinkFilter(data) {
+function externalLinkFilter(this: Hexo, data): void {
   if (!EXTERNAL_LINK_POST_ENABLED) return;
 
   const { external_link, url } = this.config;
@@ -16,7 +17,7 @@ function externalLinkFilter(data) {
   }
 
   data.content = data.content.replace(rATag, (str, href) => {
-    if (!isExternalLink(href, url, external_link.exclude) || rTargetAttr.test(str)) return str;
+    if (!isExternalLink(href, url, external_link.exclude as any) || rTargetAttr.test(str)) return str;
 
     if (rRelAttr.test(str)) {
       str = str.replace(rRelStrAttr, (relStr, rel) => {
diff --git a/lib/plugins/filter/after_post_render/index.ts b/lib/plugins/filter/after_post_render/index.ts
index 87bb8b433c..014eb0b6d0 100644
--- a/lib/plugins/filter/after_post_render/index.ts
+++ b/lib/plugins/filter/after_post_render/index.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from '../../../hexo';
+
+export = (ctx: Hexo) => {
   const { filter } = ctx.extend;
 
   filter.register('after_post_render', require('./external_link'));
diff --git a/lib/plugins/filter/after_render/external_link.ts b/lib/plugins/filter/after_render/external_link.ts
index a5d7218133..7a0168d842 100644
--- a/lib/plugins/filter/after_render/external_link.ts
+++ b/lib/plugins/filter/after_render/external_link.ts
@@ -1,4 +1,5 @@
 import { isExternalLink } from 'hexo-util';
+import Hexo from '../../../hexo';
 
 let EXTERNAL_LINK_SITE_ENABLED = true;
 const rATag = /<a(?:\s+?|\s+?[^<>]+?\s+?)href=["']((?:https?:|\/\/)[^<>"']+)["'][^<>]*>/gi;
@@ -6,7 +7,7 @@ const rTargetAttr = /target=/i;
 const rRelAttr = /rel=/i;
 const rRelStrAttr = /rel=["']([^<>"']*)["']/i;
 
-function externalLinkFilter(data) {
+function externalLinkFilter(this: Hexo, data: string): string {
   if (!EXTERNAL_LINK_SITE_ENABLED) return;
 
   const { external_link, url } = this.config;
@@ -17,7 +18,7 @@ function externalLinkFilter(data) {
   }
 
   return data.replace(rATag, (str, href) => {
-    if (!isExternalLink(href, url, external_link.exclude) || rTargetAttr.test(str)) return str;
+    if (!isExternalLink(href, url, external_link.exclude as any) || rTargetAttr.test(str)) return str;
 
     if (rRelAttr.test(str)) {
       str = str.replace(rRelStrAttr, (relStr, rel) => {
diff --git a/lib/plugins/filter/after_render/index.ts b/lib/plugins/filter/after_render/index.ts
index 509e95a0f8..a1eb862d5a 100644
--- a/lib/plugins/filter/after_render/index.ts
+++ b/lib/plugins/filter/after_render/index.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from '../../../hexo';
+
+export = (ctx: Hexo) => {
   const { filter } = ctx.extend;
 
   filter.register('after_render:html', require('./external_link'));
diff --git a/lib/plugins/filter/after_render/meta_generator.ts b/lib/plugins/filter/after_render/meta_generator.ts
index 4c04daee3a..7848f435ee 100644
--- a/lib/plugins/filter/after_render/meta_generator.ts
+++ b/lib/plugins/filter/after_render/meta_generator.ts
@@ -1,7 +1,9 @@
+import type Hexo from '../../../hexo';
+
 let NEED_INJECT = true;
 let META_GENERATOR_TAG;
 
-function hexoMetaGeneratorInject(data) {
+function hexoMetaGeneratorInject(this: Hexo, data: string): string {
   if (!NEED_INJECT) return;
 
   if (!this.config.meta_generator
diff --git a/lib/plugins/filter/before_exit/index.ts b/lib/plugins/filter/before_exit/index.ts
index ba3312749e..1443eed5cb 100644
--- a/lib/plugins/filter/before_exit/index.ts
+++ b/lib/plugins/filter/before_exit/index.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from '../../../hexo';
+
+export = (ctx: Hexo) => {
   const { filter } = ctx.extend;
 
   filter.register('before_exit', require('./save_database'));
diff --git a/lib/plugins/filter/before_exit/save_database.ts b/lib/plugins/filter/before_exit/save_database.ts
index 9aadce2ee8..9a853eb93e 100644
--- a/lib/plugins/filter/before_exit/save_database.ts
+++ b/lib/plugins/filter/before_exit/save_database.ts
@@ -1,4 +1,6 @@
-function saveDatabaseFilter() {
+import type Hexo from '../../../hexo';
+
+function saveDatabaseFilter(this: Hexo) {
   if (!this.env.init || !this._dbLoaded) return;
 
   return this.database.save().then(() => {
diff --git a/lib/plugins/filter/before_generate/index.ts b/lib/plugins/filter/before_generate/index.ts
index 288bb1651a..9c9565b9f4 100644
--- a/lib/plugins/filter/before_generate/index.ts
+++ b/lib/plugins/filter/before_generate/index.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from '../../../hexo';
+
+export = (ctx: Hexo) => {
   const { filter } = ctx.extend;
 
   filter.register('before_generate', require('./render_post'));
diff --git a/lib/plugins/filter/before_generate/render_post.ts b/lib/plugins/filter/before_generate/render_post.ts
index 539b5dadda..0a6cbe78d8 100644
--- a/lib/plugins/filter/before_generate/render_post.ts
+++ b/lib/plugins/filter/before_generate/render_post.ts
@@ -1,6 +1,7 @@
 import Promise from 'bluebird';
+import type Hexo from '../../../hexo';
 
-function renderPostFilter() {
+function renderPostFilter(this: Hexo): Promise<[any[], any[]]> {
   const renderPosts = model => {
     const posts = model.toArray().filter(post => post.content == null);
 
diff --git a/lib/plugins/filter/before_post_render/backtick_code_block.ts b/lib/plugins/filter/before_post_render/backtick_code_block.ts
index b9df3e60f2..7952169edd 100644
--- a/lib/plugins/filter/before_post_render/backtick_code_block.ts
+++ b/lib/plugins/filter/before_post_render/backtick_code_block.ts
@@ -1,3 +1,5 @@
+import type Hexo from '../../../hexo';
+
 const rBacktick = /^((?:[^\S\r\n]*>){0,3}[^\S\r\n]*)(`{3,}|~{3,})[^\S\r\n]*((?:.*?[^`\s])?)[^\S\r\n]*\n((?:[\s\S]*?\n)?)(?:(?:[^\S\r\n]*>){0,3}[^\S\r\n]*)\2[^\S\r\n]?(\n+|$)/gm;
 const rAllOptions = /([^\s]+)\s+(.+?)\s+(https?:\/\/\S+|\/\S+)\s*(.+)?/;
 const rLangCaption = /([^\s]+)\s*(.+)?/;
@@ -11,8 +13,8 @@ interface Options {
   firstLineNumber?: string | number
 }
 
-export = ctx => {
-  return function backtickCodeBlock(data) {
+export = (ctx: Hexo) => {
+  return function backtickCodeBlock(data): void {
     const dataContent = data.content;
 
     if ((!dataContent.includes('```') && !dataContent.includes('~~~')) || !ctx.extend.highlight.query(ctx.config.syntax_highlighter)) return;
diff --git a/lib/plugins/filter/before_post_render/index.ts b/lib/plugins/filter/before_post_render/index.ts
index 07bde83da3..501b483df7 100644
--- a/lib/plugins/filter/before_post_render/index.ts
+++ b/lib/plugins/filter/before_post_render/index.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from '../../../hexo';
+
+export = (ctx: Hexo) => {
   const { filter } = ctx.extend;
 
   filter.register('before_post_render', require('./backtick_code_block')(ctx));
diff --git a/lib/plugins/filter/before_post_render/titlecase.ts b/lib/plugins/filter/before_post_render/titlecase.ts
index 24e596ace8..bd149d3823 100644
--- a/lib/plugins/filter/before_post_render/titlecase.ts
+++ b/lib/plugins/filter/before_post_render/titlecase.ts
@@ -1,6 +1,6 @@
 let titlecase;
 
-function titlecaseFilter(data) {
+function titlecaseFilter(data): void {
   if (!(typeof data.titlecase !== 'undefined' ? data.titlecase : this.config.titlecase) || !data.title) return;
 
   if (!titlecase) titlecase = require('titlecase');
diff --git a/lib/plugins/filter/new_post_path.ts b/lib/plugins/filter/new_post_path.ts
index c06b946230..1eaa58c9f2 100644
--- a/lib/plugins/filter/new_post_path.ts
+++ b/lib/plugins/filter/new_post_path.ts
@@ -3,6 +3,7 @@ import moment from 'moment';
 import Promise from 'bluebird';
 import { createSha1Hash, Permalink } from 'hexo-util';
 import { ensurePath } from 'hexo-fs';
+import type Hexo from '../../hexo';
 let permalink;
 
 const reservedKeys = {
@@ -22,7 +23,7 @@ interface Data {
   date?: Date;
 }
 
-function newPostPathFilter(data: Data = {}, replace) {
+function newPostPathFilter(this: Hexo, data: Data = {}, replace): Promise<string> {
   const sourceDir = this.source_dir;
   const draftDir = join(sourceDir, '_drafts');
   const postDir = join(sourceDir, '_posts');
diff --git a/lib/plugins/filter/post_permalink.ts b/lib/plugins/filter/post_permalink.ts
index c715e67b5d..f066421330 100644
--- a/lib/plugins/filter/post_permalink.ts
+++ b/lib/plugins/filter/post_permalink.ts
@@ -1,8 +1,9 @@
 import { createSha1Hash, Permalink, slugize } from 'hexo-util';
 import { basename } from 'path';
+import type Hexo from '../../hexo';
 let permalink;
 
-function postPermalinkFilter(data) {
+function postPermalinkFilter(this: Hexo, data) {
   const { config } = this;
   const { id, _id, slug, title, date, __permalink } = data;
 
diff --git a/lib/plugins/filter/template_locals/i18n.ts b/lib/plugins/filter/template_locals/i18n.ts
index 73367d8df0..a709fe8934 100644
--- a/lib/plugins/filter/template_locals/i18n.ts
+++ b/lib/plugins/filter/template_locals/i18n.ts
@@ -1,6 +1,7 @@
 import { Pattern } from 'hexo-util';
+import type Hexo from '../../../hexo';
 
-function i18nLocalsFilter(locals) {
+function i18nLocalsFilter(this: Hexo, locals): void {
   const { i18n } = this.theme;
   const { config } = this;
   const i18nDir = config.i18n_dir;
diff --git a/lib/plugins/filter/template_locals/index.ts b/lib/plugins/filter/template_locals/index.ts
index 663cb8ab3f..27dbf0caa4 100644
--- a/lib/plugins/filter/template_locals/index.ts
+++ b/lib/plugins/filter/template_locals/index.ts
@@ -1,4 +1,6 @@
-export = ctx => {
+import type Hexo from '../../../hexo';
+
+export = (ctx: Hexo) => {
   const { filter } = ctx.extend;
 
   filter.register('template_locals', require('./i18n'));
diff --git a/lib/plugins/generator/asset.ts b/lib/plugins/generator/asset.ts
index 722807c52e..074f497620 100644
--- a/lib/plugins/generator/asset.ts
+++ b/lib/plugins/generator/asset.ts
@@ -4,13 +4,14 @@ import Promise from 'bluebird';
 import { extname } from 'path';
 import { magenta } from 'picocolors';
 import type warehouse from 'warehouse';
+import type Hexo from '../../hexo';
 
 interface Data {
   modified: boolean;
   data?: () => any;
 }
 
-const process = (name, ctx) => {
+const process = (name: string, ctx: Hexo) => {
   // @ts-expect-error
   return Promise.filter(ctx.model(name).toArray(), (asset: warehouse['Schema']) => exists(asset.source).tap(exist => {
     // @ts-expect-error
@@ -46,7 +47,7 @@ const process = (name, ctx) => {
   });
 };
 
-function assetGenerator() {
+function assetGenerator(this: Hexo): Promise<any[]> {
   return Promise.all([
     process('Asset', this),
     process('PostAsset', this)
diff --git a/lib/plugins/helper/css.ts b/lib/plugins/helper/css.ts
index 74ca0ba357..9dac2e3588 100644
--- a/lib/plugins/helper/css.ts
+++ b/lib/plugins/helper/css.ts
@@ -2,7 +2,7 @@ import { htmlTag, url_for } from 'hexo-util';
 import moize from 'moize';
 
 let relative_link = true;
-function cssHelper(...args) {
+function cssHelper(...args: any[]) {
   let result = '\n';
 
   relative_link = this.config.relative_link;
diff --git a/lib/plugins/helper/date.ts b/lib/plugins/helper/date.ts
index b347770dc8..8d45b27147 100644
--- a/lib/plugins/helper/date.ts
+++ b/lib/plugins/helper/date.ts
@@ -1,13 +1,14 @@
 import moment from 'moment-timezone';
 const { isMoment } = moment;
 import moize from 'moize';
+import type Hexo from '../../hexo';
 
-const isDate = value =>
+const isDate = (value: moment.MomentInput | moment.Moment): boolean =>
   typeof value === 'object' && value instanceof Date && !isNaN(value.getTime());
 
-function getMoment(date, lang, timezone) {
+function getMoment(date: moment.MomentInput | moment.Moment, lang: string, timezone: string): moment.Moment {
   if (date == null) date = moment();
-  if (!isMoment(date)) date = moment(isDate(date) ? date : new Date(date));
+  if (!isMoment(date)) date = moment(isDate(date) ? <Date>date : new Date(<string | number>date));
   lang = _toMomentLocale(lang);
 
   if (lang) date = date.locale(lang);
@@ -16,7 +17,7 @@ function getMoment(date, lang, timezone) {
   return date;
 }
 
-function toISOString(date) {
+function toISOString(date: string | number | Date | moment.Moment) {
   if (date == null) {
     return new Date().toISOString();
   }
@@ -25,22 +26,22 @@ function toISOString(date) {
     return date.toISOString();
   }
 
-  return new Date(date).toISOString();
+  return new Date(date as (string | number)).toISOString();
 }
 
-function dateHelper(date, format) {
+function dateHelper(date: moment.Moment | moment.MomentInput, format: string) {
   const { config } = this;
   const moment = getMoment(date, getLanguage(this), config.timezone);
   return moment.format(format || config.date_format);
 }
 
-function timeHelper(date, format) {
+function timeHelper(date: moment.Moment | moment.MomentInput, format: string) {
   const { config } = this;
   const moment = getMoment(date, getLanguage(this), config.timezone);
   return moment.format(format || config.time_format);
 }
 
-function fullDateHelper(date, format) {
+function fullDateHelper(date: moment.Moment | moment.MomentInput, format: string) {
   if (format) {
     const moment = getMoment(date, getLanguage(this), this.config.timezone);
     return moment.format(format);
@@ -49,13 +50,13 @@ function fullDateHelper(date, format) {
   return `${this.date(date)} ${this.time(date)}`;
 }
 
-function relativeDateHelper(date) {
+function relativeDateHelper(date: moment.Moment | moment.MomentInput) {
   const { config } = this;
   const moment = getMoment(date, getLanguage(this), config.timezone);
   return moment.fromNow();
 }
 
-function timeTagHelper(date, format) {
+function timeTagHelper(date: string | number | Date | moment.Moment, format: string) {
   const { config } = this;
   return `<time datetime="${toISOString(date)}">${this.date(date, format, getLanguage(this), config.timezone)}</time>`;
 }
@@ -72,7 +73,7 @@ function getLanguage(ctx) {
  *
  * Moment defined locales: https://github.com/moment/moment/tree/master/locale
  */
-function _toMomentLocale(lang) {
+function _toMomentLocale(lang: string) {
   if (lang === undefined) {
     return undefined;
   }
diff --git a/lib/plugins/helper/debug.ts b/lib/plugins/helper/debug.ts
index ba4a96983f..a097223bb9 100644
--- a/lib/plugins/helper/debug.ts
+++ b/lib/plugins/helper/debug.ts
@@ -1,12 +1,12 @@
 import { inspect } from 'util';
 
 // this format object as string, resolves circular reference
-function inspectObject(object, options) {
+function inspectObject(object: any, options: boolean) {
   return inspect(object, options);
 }
 
 // wrapper to log to console
-function log(...args) {
+function log(...args: any[]) {
   return Reflect.apply(console.log, null, args);
 }
 
diff --git a/lib/plugins/helper/favicon_tag.ts b/lib/plugins/helper/favicon_tag.ts
index 579c04379a..3c00b5dbd5 100644
--- a/lib/plugins/helper/favicon_tag.ts
+++ b/lib/plugins/helper/favicon_tag.ts
@@ -1,6 +1,6 @@
 import { url_for } from 'hexo-util';
 
-function faviconTagHelper(path) {
+function faviconTagHelper(path: string) {
   return `<link rel="shortcut icon" href="${url_for.call(this, path)}">`;
 }
 
diff --git a/lib/plugins/helper/feed_tag.ts b/lib/plugins/helper/feed_tag.ts
index 8fccfc7738..bb8bca13ab 100644
--- a/lib/plugins/helper/feed_tag.ts
+++ b/lib/plugins/helper/feed_tag.ts
@@ -11,7 +11,7 @@ interface Options {
   type?: string;
 }
 
-function makeFeedTag(path, options: Options = {}, configFeed?, configTitle?) {
+function makeFeedTag(path: string, options: Options = {}, configFeed?: any, configTitle?: string) {
   const title = options.title || configTitle;
 
   if (path) {
@@ -46,7 +46,7 @@ function makeFeedTag(path, options: Options = {}, configFeed?, configTitle?) {
   return '';
 }
 
-function feedTagHelper(path, options = {}) {
+function feedTagHelper(path: string, options = {}) {
   const { config } = this;
   return moize.deep(makeFeedTag.bind(this))(path, options, config.feed, config.title);
 }
diff --git a/lib/plugins/helper/format.ts b/lib/plugins/helper/format.ts
index c9372b507e..745e9901ff 100644
--- a/lib/plugins/helper/format.ts
+++ b/lib/plugins/helper/format.ts
@@ -3,7 +3,7 @@ import titlecase from 'titlecase';
 export {stripHTML as strip_html};
 export {stripHTML};
 
-export function trim(str) {
+export function trim(str: string) {
   return str.trim();
 }
 
diff --git a/lib/plugins/helper/fragment_cache.ts b/lib/plugins/helper/fragment_cache.ts
index 1c38229e0c..91926b919f 100644
--- a/lib/plugins/helper/fragment_cache.ts
+++ b/lib/plugins/helper/fragment_cache.ts
@@ -1,7 +1,7 @@
-
 import { Cache } from 'hexo-util';
+import type Hexo from '../../hexo';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   const cache = new Cache();
 
   // reset cache for watch mode
diff --git a/lib/plugins/helper/full_url_for.ts b/lib/plugins/helper/full_url_for.ts
index 4e77338082..9484f0e537 100644
--- a/lib/plugins/helper/full_url_for.ts
+++ b/lib/plugins/helper/full_url_for.ts
@@ -1,6 +1,6 @@
 
 import { full_url_for } from 'hexo-util';
 
-export = function(path) {
+export = function(path: string) {
   return full_url_for.call(this, path);
 }
diff --git a/lib/plugins/helper/js.ts b/lib/plugins/helper/js.ts
index 24ca0fca3d..8ca44e5c52 100644
--- a/lib/plugins/helper/js.ts
+++ b/lib/plugins/helper/js.ts
@@ -2,7 +2,7 @@ import { htmlTag, url_for } from 'hexo-util';
 import moize from 'moize';
 
 let relative_link = true;
-function jsHelper(...args) {
+function jsHelper(...args: any[]) {
   let result = '\n';
 
   relative_link = this.config.relative_link;
diff --git a/lib/plugins/helper/list_categories.ts b/lib/plugins/helper/list_categories.ts
index ff248d6bf3..b2c1fd4e58 100644
--- a/lib/plugins/helper/list_categories.ts
+++ b/lib/plugins/helper/list_categories.ts
@@ -33,7 +33,7 @@ function listCategoriesHelper(categories, options) {
   const hierarchicalList = (level: number, parent?: any) => {
     let result = '';
 
-    prepareQuery(parent).forEach((cat, i) => {
+    prepareQuery(parent).forEach(cat => {
       let child;
       if (!depth || level + 1 < depth) {
         child = hierarchicalList(level + 1, cat._id);
diff --git a/lib/plugins/helper/mail_to.ts b/lib/plugins/helper/mail_to.ts
index 90f9ef88c9..be102ef516 100644
--- a/lib/plugins/helper/mail_to.ts
+++ b/lib/plugins/helper/mail_to.ts
@@ -14,7 +14,7 @@ interface Attrs {
   [key: string]: string | boolean | null | undefined;
 }
 
-function mailToHelper(path, text, options: Options = {}) {
+function mailToHelper(path: string, text: string, options: Options = {}) {
   if (Array.isArray(path)) path = path.join(',');
   if (!text) text = path;
 
diff --git a/lib/plugins/helper/markdown.ts b/lib/plugins/helper/markdown.ts
index 956425f072..9465bbb671 100644
--- a/lib/plugins/helper/markdown.ts
+++ b/lib/plugins/helper/markdown.ts
@@ -1,4 +1,4 @@
-function markdownHelper(text, options) {
+function markdownHelper(text: string, options) {
   return this.render(text, 'markdown', options);
 }
 
diff --git a/lib/plugins/helper/open_graph.ts b/lib/plugins/helper/open_graph.ts
index 9209eeda63..27d142f8bc 100644
--- a/lib/plugins/helper/open_graph.ts
+++ b/lib/plugins/helper/open_graph.ts
@@ -34,7 +34,7 @@ const localeToTerritory = moize.shallow(str => {
   }
 });
 
-const meta = (name, content, escape?: boolean) => {
+const meta = (name: string, content: string | URL, escape?: boolean) => {
   if (escape !== false && typeof content === 'string') {
     content = escapeHTML(content);
   }
@@ -43,7 +43,7 @@ const meta = (name, content, escape?: boolean) => {
   return `<meta name="${name}">\n`;
 };
 
-const og = (name, content?: string, escape?: boolean) => {
+const og = (name: string, content?: string, escape?: boolean) => {
   if (escape !== false && typeof content === 'string') {
     content = escapeHTML(content);
   }
diff --git a/lib/plugins/helper/paginator.ts b/lib/plugins/helper/paginator.ts
index 8d37c80739..429aff8b4d 100644
--- a/lib/plugins/helper/paginator.ts
+++ b/lib/plugins/helper/paginator.ts
@@ -1,12 +1,35 @@
 import { htmlTag, url_for } from 'hexo-util';
+import type Hexo from '../../hexo';
 
-const createLink = (options, ctx) => {
+interface Options {
+  base?: string;
+  current?: number;
+  format?: string;
+  total?: number;
+  end_size?: number;
+  mid_size?: number;
+  space?: string;
+  next_text?: string;
+  prev_text?: string;
+  prev_next?: boolean;
+  escape?: boolean;
+  page_class?: string;
+  current_class?: string;
+  space_class?: string;
+  prev_class?: string;
+  next_class?: string;
+  force_prev_next?: boolean;
+  show_all?: boolean;
+  transform?: (i: number) => any;
+}
+
+const createLink = (options: Options, ctx: Hexo) => {
   const { base, format } = options;
 
-  return i => url_for.call(ctx, i === 1 ? base : base + format.replace('%d', i));
+  return (i: number) => url_for.call(ctx, i === 1 ? base : base + format.replace('%d', String(i)));
 };
 
-const createPageTag = (options, ctx) => {
+const createPageTag = (options: Options, ctx: Hexo) => {
   const link = createLink(options, ctx);
   const {
     current,
@@ -16,7 +39,7 @@ const createPageTag = (options, ctx) => {
     current_class: currentClass
   } = options;
 
-  return i => {
+  return (i: number) => {
     if (i === current) {
       return htmlTag('span', { class: pageClass + ' ' + currentClass }, transform ? transform(i) : i, escape);
     }
@@ -24,7 +47,7 @@ const createPageTag = (options, ctx) => {
   };
 };
 
-const showAll = (tags, options, ctx) => {
+const showAll = (tags: string[], options: Options, ctx: Hexo) => {
   const { total } = options;
 
   const pageLink = createPageTag(options, ctx);
@@ -34,7 +57,7 @@ const showAll = (tags, options, ctx) => {
   }
 };
 
-const paginationPartShow = (tags, options, ctx) => {
+const paginationPartShow = (tags, options, ctx: Hexo) => {
   const {
     current,
     total,
@@ -86,27 +109,6 @@ const paginationPartShow = (tags, options, ctx) => {
   }
 };
 
-interface Options {
-  base?: string;
-  current?: number;
-  format?: string;
-  total?: number;
-  end_size?: number;
-  mid_size?: number;
-  space?: string;
-  next_text?: string;
-  prev_text?: string;
-  prev_next?: boolean;
-  escape?: boolean;
-  page_class?: string;
-  current_class?: string;
-  space_class?: string;
-  prev_class?: string;
-  next_class?: string;
-  force_prev_next?: boolean;
-  show_all?: boolean;
-}
-
 function paginatorHelper(options: Options = {}) {
   options = Object.assign({
     base: this.page.base || '',
diff --git a/lib/plugins/helper/partial.ts b/lib/plugins/helper/partial.ts
index d548a58ba9..fac560117d 100644
--- a/lib/plugins/helper/partial.ts
+++ b/lib/plugins/helper/partial.ts
@@ -1,11 +1,12 @@
 import { dirname, join } from 'path';
+import type Hexo from '../../hexo';
 
 interface Options {
   cache?: boolean | string;
   only?: boolean;
 }
 
-export = ctx => function partial(name, locals, options: Options = {}) {
+export = (ctx: Hexo) => function partial(name: string, locals: any, options: Options = {}) {
   if (typeof name !== 'string') throw new TypeError('name must be a string!');
 
   const { cache } = options;
diff --git a/lib/plugins/helper/relative_url.ts b/lib/plugins/helper/relative_url.ts
index 631a9946fd..62ebaa16e2 100644
--- a/lib/plugins/helper/relative_url.ts
+++ b/lib/plugins/helper/relative_url.ts
@@ -1,5 +1,5 @@
 import { relative_url } from 'hexo-util';
 
-export = function(from, to) {
+export = function(from: string, to: string) {
   return relative_url(from, to);
 }
diff --git a/lib/plugins/helper/render.ts b/lib/plugins/helper/render.ts
index 9f8473efb3..4d2d7414b3 100644
--- a/lib/plugins/helper/render.ts
+++ b/lib/plugins/helper/render.ts
@@ -1,4 +1,6 @@
-export = ctx => function render(text, engine, options) {
+import type Hexo from '../../hexo';
+
+export = (ctx: Hexo) => function render(text: string, engine: string, options:object = {}) {
   return ctx.render.renderSync({
     text,
     engine
diff --git a/lib/plugins/helper/toc.ts b/lib/plugins/helper/toc.ts
index 4abec4d30b..02a4b1ad7d 100644
--- a/lib/plugins/helper/toc.ts
+++ b/lib/plugins/helper/toc.ts
@@ -13,7 +13,7 @@ interface Options {
   list_number?: boolean;
 }
 
-function tocHelper(str, options: Options = {}) {
+function tocHelper(str: string, options: Options = {}) {
   options = Object.assign({
     min_depth: 1,
     max_depth: 6,
diff --git a/lib/plugins/helper/url_for.ts b/lib/plugins/helper/url_for.ts
index 49e7a5f124..e7c58dd05d 100644
--- a/lib/plugins/helper/url_for.ts
+++ b/lib/plugins/helper/url_for.ts
@@ -1,5 +1,9 @@
 import { url_for } from 'hexo-util';
 
-export = function(path, options) {
+interface Options {
+  relative?: boolean
+}
+
+export = function(path: string, options: Options = {}) {
   return url_for.call(this, path, options);
 }
diff --git a/lib/plugins/processor/asset.ts b/lib/plugins/processor/asset.ts
index 9693bbaeb5..c56ff62052 100644
--- a/lib/plugins/processor/asset.ts
+++ b/lib/plugins/processor/asset.ts
@@ -4,8 +4,11 @@ import { parse as yfm } from 'hexo-front-matter';
 import { extname, relative } from 'path';
 import { Pattern } from 'hexo-util';
 import { magenta } from 'picocolors';
+import type { _File } from '../../box';
+import type Hexo from '../../hexo';
+import type { Stats } from 'fs';
 
-export = ctx => {
+export = (ctx: Hexo) => {
   return {
     pattern: new Pattern(path => {
       if (isExcludedFile(path, ctx.config)) return;
@@ -15,7 +18,7 @@ export = ctx => {
       };
     }),
 
-    process: function assetProcessor(file) {
+    process: function assetProcessor(file: _File) {
       if (file.params.renderable) {
         return processPage(ctx, file);
       }
@@ -25,7 +28,7 @@ export = ctx => {
   };
 };
 
-function processPage(ctx, file) {
+function processPage(ctx: Hexo, file: _File) {
   const Page = ctx.model('Page');
   const { path } = file;
   const doc = Page.findOne({source: path});
@@ -48,7 +51,7 @@ function processPage(ctx, file) {
   return Promise.all([
     file.stat(),
     file.read()
-  ]).spread((stats, content) => {
+  ]).spread((stats: Stats, content: string) => {
     const data = yfm(content);
     const output = ctx.render.getOutput(path);
 
@@ -105,7 +108,7 @@ function processPage(ctx, file) {
   });
 }
 
-function processAsset(ctx, file) {
+function processAsset(ctx: Hexo, file: _File) {
   const id = relative(ctx.base_dir, file.source).replace(/\\/g, '/');
   const Asset = ctx.model('Asset');
   const doc = Asset.findById(id);
diff --git a/lib/plugins/processor/common.ts b/lib/plugins/processor/common.ts
index c981536598..fa5202b633 100644
--- a/lib/plugins/processor/common.ts
+++ b/lib/plugins/processor/common.ts
@@ -4,21 +4,21 @@ import micromatch from 'micromatch';
 
 const DURATION_MINUTE = 1000 * 60;
 
-function isMatch(path, patterns) {
+function isMatch(path: string, patterns: string| string[]) {
   if (!patterns) return false;
 
   return micromatch.isMatch(path, patterns);
 }
 
-function isTmpFile(path) {
+function isTmpFile(path: string) {
   return path.endsWith('%') || path.endsWith('~');
 }
 
-function isHiddenFile(path) {
+function isHiddenFile(path: string) {
   return /(^|\/)[_.]/.test(path);
 }
 
-function isExcludedFile(path, config) {
+function isExcludedFile(path: string, config) {
   if (isTmpFile(path)) return true;
   if (isMatch(path, config.exclude)) return true;
   if (isHiddenFile(path) && !isMatch(path, config.include)) return true;
@@ -34,7 +34,7 @@ export {isTmpFile};
 export {isHiddenFile};
 export {isExcludedFile};
 
-export function toDate(date) {
+export function toDate(date: string | number | Date) {
   if (!date || moment.isMoment(date)) return date;
 
   if (!(date instanceof Date)) {
@@ -46,7 +46,7 @@ export function toDate(date) {
   return date;
 }
 
-export function timezone(date, timezone) {
+export function timezone(date: Date, timezone: string) {
   if (moment.isMoment(date)) date = date.toDate();
 
   const offset = date.getTimezoneOffset();
diff --git a/lib/plugins/processor/data.ts b/lib/plugins/processor/data.ts
index 7757e7c99c..6db47b3097 100644
--- a/lib/plugins/processor/data.ts
+++ b/lib/plugins/processor/data.ts
@@ -1,10 +1,12 @@
 import { Pattern } from 'hexo-util';
 import { extname } from 'path';
+import type Hexo from '../../hexo';
+import type { _File } from '../../box';
 
-export = ctx => ({
+export = (ctx: Hexo) => ({
   pattern: new Pattern('_data/*path'),
 
-  process: function dataProcessor(file) {
+  process: function dataProcessor(file: _File) {
     const Data = ctx.model('Data');
     const { path } = file.params;
     const id = path.substring(0, path.length - extname(path).length);
diff --git a/lib/plugins/processor/post.ts b/lib/plugins/processor/post.ts
index 9c61a561b8..c9ec3a1a86 100644
--- a/lib/plugins/processor/post.ts
+++ b/lib/plugins/processor/post.ts
@@ -5,6 +5,9 @@ import { extname, join } from 'path';
 import { stat, listDir } from 'hexo-fs';
 import { slugize, Pattern, Permalink } from 'hexo-util';
 import { magenta } from 'picocolors';
+import type { _File } from '../../box';
+import type Hexo from '../../hexo';
+import type { Stats } from 'fs';
 
 const postDir = '_posts/';
 const draftDir = '_drafts/';
@@ -20,7 +23,7 @@ const preservedKeys = {
   hash: true
 };
 
-export = ctx => {
+export = (ctx: Hexo) => {
   return {
     pattern: new Pattern(path => {
       if (isTmpFile(path)) return;
@@ -62,7 +65,7 @@ export = ctx => {
   };
 };
 
-function processPost(ctx, file) {
+function processPost(ctx: Hexo, file: _File) {
   const Post = ctx.model('Post');
   const { path } = file.params;
   const doc = Post.findOne({source: file.path});
@@ -86,7 +89,7 @@ function processPost(ctx, file) {
   return Promise.all([
     file.stat(),
     file.read()
-  ]).spread((stats, content) => {
+  ]).spread((stats: Stats, content: string) => {
     const data = yfm(content);
     const info = parseFilename(config.new_post_name, path);
     const keys = Object.keys(info);
@@ -179,7 +182,7 @@ function processPost(ctx, file) {
   ]));
 }
 
-function parseFilename(config, path) {
+function parseFilename(config: string, path: string) {
   config = config.substring(0, config.length - extname(config).length);
   path = path.substring(0, path.length - extname(path).length);
 
@@ -212,7 +215,7 @@ function parseFilename(config, path) {
   };
 }
 
-function scanAssetDir(ctx, post) {
+function scanAssetDir(ctx: Hexo, post) {
   if (!ctx.config.post_asset_folder) return;
 
   const assetDir = post.asset_dir;
@@ -246,7 +249,7 @@ function scanAssetDir(ctx, post) {
   });
 }
 
-function shouldSkipAsset(ctx, post, asset) {
+function shouldSkipAsset(ctx: Hexo, post, asset) {
   if (!ctx._showDrafts()) {
     if (post.published === false && asset) {
       // delete existing draft assets if draft posts are hidden
@@ -261,7 +264,7 @@ function shouldSkipAsset(ctx, post, asset) {
   return asset !== undefined; // skip already existing assets
 }
 
-function processAsset(ctx, file) {
+function processAsset(ctx: Hexo, file: _File) {
   const PostAsset = ctx.model('PostAsset');
   const Post = ctx.model('Post');
   const id = file.source.substring(ctx.base_dir.length).replace(/\\/g, '/');
diff --git a/lib/plugins/renderer/json.ts b/lib/plugins/renderer/json.ts
index 7c87cf6ecb..c5d02377f9 100644
--- a/lib/plugins/renderer/json.ts
+++ b/lib/plugins/renderer/json.ts
@@ -1,4 +1,6 @@
-function jsonRenderer(data) {
+import type { StoreFunctionData } from '../../extend/renderer';
+
+function jsonRenderer(data: StoreFunctionData) {
   return JSON.parse(data.text);
 }
 
diff --git a/lib/plugins/renderer/nunjucks.ts b/lib/plugins/renderer/nunjucks.ts
index 1ba4ba0205..ccb0281346 100644
--- a/lib/plugins/renderer/nunjucks.ts
+++ b/lib/plugins/renderer/nunjucks.ts
@@ -1,6 +1,7 @@
-import nunjucks from 'nunjucks';
+import nunjucks, { Environment } from 'nunjucks';
 import { readFileSync } from 'hexo-fs';
 import { dirname } from 'path';
+import type { StoreFunctionData } from '../../extend/renderer';
 
 function toArray(value) {
   if (Array.isArray(value)) {
@@ -36,13 +37,13 @@ const nunjucksCfg = {
   lstripBlocks: false
 };
 
-const nunjucksAddFilter = env => {
+const nunjucksAddFilter = (env: Environment) => {
   env.addFilter('toarray', toArray);
   env.addFilter('safedump', safeJsonStringify);
 };
 
-function njkCompile(data) {
-  let env;
+function njkCompile(data: StoreFunctionData) {
+  let env: Environment;
   if (data.path) {
     env = nunjucks.configure(dirname(data.path), nunjucksCfg);
   } else {
@@ -52,14 +53,14 @@ function njkCompile(data) {
 
   const text = 'text' in data ? data.text : readFileSync(data.path);
 
-  return nunjucks.compile(text, env, data.path);
+  return nunjucks.compile(text as string, env, data.path);
 }
 
-function njkRenderer(data, locals) {
+function njkRenderer(data: StoreFunctionData, locals: object) {
   return njkCompile(data).render(locals);
 }
 
-njkRenderer.compile = data => {
+njkRenderer.compile = (data: StoreFunctionData) => {
   // Need a closure to keep the compiled template.
   return locals => njkCompile(data).render(locals);
 };
diff --git a/lib/plugins/renderer/plain.ts b/lib/plugins/renderer/plain.ts
index e1aa47f2df..99c35a1c1c 100644
--- a/lib/plugins/renderer/plain.ts
+++ b/lib/plugins/renderer/plain.ts
@@ -1,4 +1,6 @@
-function plainRenderer(data) {
+import type { StoreFunctionData } from '../../extend/renderer';
+
+function plainRenderer(data: StoreFunctionData) {
   return data.text;
 }
 
diff --git a/lib/plugins/renderer/yaml.ts b/lib/plugins/renderer/yaml.ts
index a8f0af4a34..fd460d14a0 100644
--- a/lib/plugins/renderer/yaml.ts
+++ b/lib/plugins/renderer/yaml.ts
@@ -1,6 +1,7 @@
 import yaml from 'js-yaml';
 import { escape } from 'hexo-front-matter';
 import logger from 'hexo-log';
+import type { StoreFunctionData } from '../../extend/renderer';
 
 let schema = {};
 // FIXME: workaround for https://github.com/hexojs/hexo/issues/4917
@@ -14,7 +15,7 @@ try {
   }
 }
 
-function yamlHelper(data) {
+function yamlHelper(data: StoreFunctionData) {
   return yaml.load(escape(data.text), { schema });
 }
 
diff --git a/lib/plugins/tag/asset_img.ts b/lib/plugins/tag/asset_img.ts
index e608b499ff..8a9941b74a 100644
--- a/lib/plugins/tag/asset_img.ts
+++ b/lib/plugins/tag/asset_img.ts
@@ -1,5 +1,6 @@
 import img from './img';
 import { encodeURL } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 /**
  * Asset image tag
@@ -7,10 +8,10 @@ import { encodeURL } from 'hexo-util';
  * Syntax:
  *   {% asset_img [class names] slug [width] [height] [title text [alt text]]%}
  */
-export = ctx => {
+export = (ctx: Hexo) => {
   const PostAsset = ctx.model('PostAsset');
 
-  return function assetImgTag(args) {
+  return function assetImgTag(args: string[]) {
     const len = args.length;
 
     // Find image URL
diff --git a/lib/plugins/tag/asset_link.ts b/lib/plugins/tag/asset_link.ts
index eb07087625..f132730db2 100644
--- a/lib/plugins/tag/asset_link.ts
+++ b/lib/plugins/tag/asset_link.ts
@@ -1,4 +1,5 @@
 import { encodeURL, escapeHTML } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 /**
  * Asset link tag
@@ -6,10 +7,10 @@ import { encodeURL, escapeHTML } from 'hexo-util';
  * Syntax:
  *   {% asset_link slug [title] [escape] %}
  */
-export = ctx => {
+export = (ctx: Hexo) => {
   const PostAsset = ctx.model('PostAsset');
 
-  return function assetLinkTag(args) {
+  return function assetLinkTag(args: string[]) {
     const slug = args.shift();
     if (!slug) return;
 
diff --git a/lib/plugins/tag/asset_path.ts b/lib/plugins/tag/asset_path.ts
index 7242e3ce73..60e4c31746 100644
--- a/lib/plugins/tag/asset_path.ts
+++ b/lib/plugins/tag/asset_path.ts
@@ -1,4 +1,5 @@
 import { encodeURL } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 /**
  * Asset path tag
@@ -6,10 +7,10 @@ import { encodeURL } from 'hexo-util';
  * Syntax:
  *   {% asset_path slug %}
  */
-export = ctx => {
+export = (ctx: Hexo) => {
   const PostAsset = ctx.model('PostAsset');
 
-  return function assetPathTag(args) {
+  return function assetPathTag(args: string[]) {
     const slug = args.shift();
     if (!slug) return;
 
diff --git a/lib/plugins/tag/blockquote.ts b/lib/plugins/tag/blockquote.ts
index 1f99e67c1a..d523e6b994 100644
--- a/lib/plugins/tag/blockquote.ts
+++ b/lib/plugins/tag/blockquote.ts
@@ -1,6 +1,7 @@
 // Based on: https://raw.github.com/imathis/octopress/master/plugins/blockquote.rb
 
 import titlecase from 'titlecase';
+import type Hexo from '../../hexo';
 
 const rFullCiteWithTitle = /(\S.*)\s+(https?:\/\/\S+)\s+(.+)/i;
 const rFullCite = /(\S.*)\s+(https?:\/\/\S+)/i;
@@ -10,7 +11,7 @@ const rAuthorTitle = /([^,]+),\s*([^,]+)/;
  * @param {string[]} args
  * @param {Hexo} ctx
  */
-const parseFooter = (args, ctx) => {
+const parseFooter = (args: string[], ctx: Hexo) => {
   const str = args.join(' ');
   if (!str) return '';
 
@@ -55,7 +56,7 @@ const parseFooter = (args, ctx) => {
 *   {% endblockquote %}
 */
 
-export = ctx => function blockquoteTag(args, content) {
+export = (ctx: Hexo) => function blockquoteTag(args: string[], content: string) {
   const footer = parseFooter(args, ctx);
 
   let result = '<blockquote>';
diff --git a/lib/plugins/tag/code.ts b/lib/plugins/tag/code.ts
index 266bda70e2..e56e2122c4 100644
--- a/lib/plugins/tag/code.ts
+++ b/lib/plugins/tag/code.ts
@@ -1,23 +1,13 @@
 // Based on: https://raw.github.com/imathis/octopress/master/plugins/code_block.rb
 
 import { escapeHTML } from 'hexo-util';
+import type Hexo from '../../hexo';
+import type { HighlightOptions } from '../../extend/syntax_highlight';
 
 const rCaptionUrlTitle = /(\S[\S\s]*)\s+(https?:\/\/\S+)\s+(.+)/i;
 const rCaptionUrl = /(\S[\S\s]*)\s+(https?:\/\/\S+)/i;
 const rCaption = /\S[\S\s]*/;
 
-interface Options {
-  lang: string;
-  language_attr: boolean;
-  firstLine: number;
-  caption: string;
-  line_number: boolean;
-  line_threshold: number;
-  mark: number[];
-  wrap: boolean;
-  lines_length?: number;
-}
-
 /**
  * Code block tag
  * Syntax:
@@ -37,11 +27,11 @@ interface Options {
  * @returns {String} Code snippet with code highlighting
 */
 
-function parseArgs(args): Options {
+function parseArgs(args: string[]): HighlightOptions {
   const _else = [];
   const len = args.length;
-  let lang, language_attr,
-    line_number, line_threshold, wrap;
+  let lang: string, language_attr: boolean,
+    line_number: boolean, line_threshold: number, wrap: boolean;
   let firstLine = 1;
   const mark = [];
   for (let i = 0; i < len; i++) {
@@ -63,10 +53,10 @@ function parseArgs(args): Options {
         line_number = value === 'true';
         break;
       case 'line_threshold':
-        if (!isNaN(value)) line_threshold = +value;
+        if (!isNaN(Number(value))) line_threshold = +value;
         break;
       case 'first_line':
-        if (!isNaN(value)) firstLine = +value;
+        if (!isNaN(Number(value))) firstLine = +value;
         break;
       case 'wrap':
         wrap = value === 'true';
@@ -88,7 +78,7 @@ function parseArgs(args): Options {
               mark.push(a);
             }
           }
-          if (!isNaN(cur)) mark.push(+cur);
+          if (!isNaN(Number(cur))) mark.push(+cur);
         }
         break;
       }
@@ -126,14 +116,14 @@ function parseArgs(args): Options {
   };
 }
 
-export = ctx => function codeTag(args, content) {
+export = (ctx: Hexo) => function codeTag(args: string[], content: string) {
 
   // If neither highlight.js nor prism.js is enabled, return escaped code directly
   if (!ctx.extend.highlight.query(ctx.config.syntax_highlighter)) {
     return `<pre><code>${escapeHTML(content)}</code></pre>`;
   }
 
-  let index;
+  let index: number;
   let enableHighlight = true;
 
   if ((index = args.findIndex(item => item.startsWith('highlight:'))) !== -1) {
diff --git a/lib/plugins/tag/full_url_for.ts b/lib/plugins/tag/full_url_for.ts
index 6dd2ff76b8..887b2f07c7 100644
--- a/lib/plugins/tag/full_url_for.ts
+++ b/lib/plugins/tag/full_url_for.ts
@@ -1,4 +1,5 @@
 import { full_url_for, htmlTag } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 /**
  * Full url for tag
@@ -6,7 +7,7 @@ import { full_url_for, htmlTag } from 'hexo-util';
  * Syntax:
  *   {% full_url_for text path %}
  */
-export = ctx => {
+export = (ctx: Hexo) => {
   return function fullUrlForTag([text, path]) {
     const url = full_url_for.call(ctx, path);
     const attrs = {
diff --git a/lib/plugins/tag/iframe.ts b/lib/plugins/tag/iframe.ts
index f1e6b2663d..9597a809a7 100644
--- a/lib/plugins/tag/iframe.ts
+++ b/lib/plugins/tag/iframe.ts
@@ -7,7 +7,7 @@ import { htmlTag } from 'hexo-util';
 *   {% iframe url [width] [height] %}
 */
 
-function iframeTag(args) {
+function iframeTag(args: string[]) {
   const src = args[0];
   const width = args[1] && args[1] !== 'default' ? args[1] : '100%';
   const height = args[2] && args[2] !== 'default' ? args[2] : '300';
diff --git a/lib/plugins/tag/img.ts b/lib/plugins/tag/img.ts
index 22e4970020..2e8b1c8d29 100644
--- a/lib/plugins/tag/img.ts
+++ b/lib/plugins/tag/img.ts
@@ -1,4 +1,5 @@
 import { htmlTag, url_for } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 const rUrl = /((([A-Za-z]{3,9}:(?:\/\/)?)(?:[-;:&=+$,\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=+$,\w]+@)[A-Za-z0-9.-]+)((?:\/[+~%/.\w-_]*)?\??(?:[-+=&;%@.\w_]*)#?(?:[.!/\\w]*))?)/;
 const rMetaDoubleQuote = /"?([^"]+)?"?/;
@@ -10,9 +11,9 @@ const rMetaSingleQuote = /'?([^']+)?'?/;
 * Syntax:
 *   {% img [class names] /path/to/image [width] [height] [title text [alt text]] %}
 */
-export = ctx => {
+export = (ctx: Hexo) => {
 
-  return function imgTag(args) {
+  return function imgTag(args: string[]) {
     const classes = [];
     let src, width, height, title, alt;
 
diff --git a/lib/plugins/tag/include_code.ts b/lib/plugins/tag/include_code.ts
index 8457c75294..78edbe1bdb 100644
--- a/lib/plugins/tag/include_code.ts
+++ b/lib/plugins/tag/include_code.ts
@@ -1,5 +1,6 @@
 import { exists, readFile } from 'hexo-fs';
 import { basename, extname, join, posix } from 'path';
+import type Hexo from '../../hexo';
 
 const rCaptionTitleFile = /(.*)?(?:\s+|^)(\/*\S+)/;
 const rLang = /\s*lang:(\w+)/i;
@@ -13,7 +14,7 @@ const rTo = /\s*to:(\d+)/i;
 *   {% include_code [title] [lang:language] path/to/file %}
 */
 
-export = ctx => function includeCodeTag(args) {
+export = (ctx: Hexo) => function includeCodeTag(args: string[]) {
   let codeDir = ctx.config.code_dir;
   let arg = args.join(' ');
 
diff --git a/lib/plugins/tag/index.ts b/lib/plugins/tag/index.ts
index b2306d36e4..8f3d303db2 100644
--- a/lib/plugins/tag/index.ts
+++ b/lib/plugins/tag/index.ts
@@ -52,7 +52,7 @@ export default (ctx: Hexo) => {
 // Use WeakMap to track different ctx (in case there is any)
 const moized = new WeakMap();
 
-export function postFindOneFactory(ctx) {
+export function postFindOneFactory(ctx: Hexo) {
   if (moized.has(ctx)) {
     return moized.get(ctx);
   }
@@ -66,7 +66,7 @@ export function postFindOneFactory(ctx) {
   return moizedPostFindOne;
 }
 
-function createPostFindOne(ctx) {
+function createPostFindOne(ctx: Hexo) {
   const Post = ctx.model('Post');
   return Post.findOne.bind(Post);
 }
diff --git a/lib/plugins/tag/link.ts b/lib/plugins/tag/link.ts
index 0df202b574..b0afbacfcd 100644
--- a/lib/plugins/tag/link.ts
+++ b/lib/plugins/tag/link.ts
@@ -9,7 +9,7 @@ const rUrl = /((([A-Za-z]{3,9}:(?:\/\/)?)(?:[-;:&=+$,\w]+@)?[A-Za-z0-9.-]+|(?:ww
 *   {% link text url [external] [title] %}
 */
 
-function linkTag(args, content) {
+function linkTag(args: string[]) {
   let url = '';
   const text = [];
   let external = false;
diff --git a/lib/plugins/tag/post_link.ts b/lib/plugins/tag/post_link.ts
index 782714a1d2..577b1319ef 100644
--- a/lib/plugins/tag/post_link.ts
+++ b/lib/plugins/tag/post_link.ts
@@ -1,5 +1,6 @@
 import { encodeURL, escapeHTML } from 'hexo-util';
 import { postFindOneFactory } from './';
+import type Hexo from '../../hexo';
 
 /**
  * Post link tag
@@ -7,8 +8,8 @@ import { postFindOneFactory } from './';
  * Syntax:
  *   {% post_link slug | title [title] [escape] %}
  */
-export = ctx => {
-  return function postLinkTag(args) {
+export = (ctx: Hexo) => {
+  return function postLinkTag(args: string[]) {
     const slug = args.shift();
     if (!slug) {
       throw new Error(`Post not found: "${slug}" doesn't exist for {% post_link %}`);
diff --git a/lib/plugins/tag/post_path.ts b/lib/plugins/tag/post_path.ts
index e9aec212f2..fdc33eccab 100644
--- a/lib/plugins/tag/post_path.ts
+++ b/lib/plugins/tag/post_path.ts
@@ -1,5 +1,6 @@
 import { encodeURL } from 'hexo-util';
 import { postFindOneFactory } from './';
+import type Hexo from '../../hexo';
 
 /**
  * Post path tag
@@ -7,8 +8,8 @@ import { postFindOneFactory } from './';
  * Syntax:
  *   {% post_path slug | title %}
  */
-export = ctx => {
-  return function postPathTag(args) {
+export = (ctx: Hexo) => {
+  return function postPathTag(args: any[]) {
     const slug = args.shift();
     if (!slug) return;
 
diff --git a/lib/plugins/tag/pullquote.ts b/lib/plugins/tag/pullquote.ts
index 1235a26d9e..89bf01697a 100644
--- a/lib/plugins/tag/pullquote.ts
+++ b/lib/plugins/tag/pullquote.ts
@@ -1,3 +1,5 @@
+import type Hexo from '../../hexo';
+
 /**
 * Pullquote tag
 *
@@ -6,7 +8,7 @@
 *   Quote string
 *   {% endpullquote %}
 */
-export = ctx => function pullquoteTag(args, content) {
+export = (ctx: Hexo) => function pullquoteTag(args: string[], content: string) {
   args.unshift('pullquote');
 
   const result = ctx.render.renderSync({text: content, engine: 'markdown'});
diff --git a/lib/plugins/tag/url_for.ts b/lib/plugins/tag/url_for.ts
index 6fb3750886..a417fa6219 100644
--- a/lib/plugins/tag/url_for.ts
+++ b/lib/plugins/tag/url_for.ts
@@ -1,4 +1,5 @@
 import { url_for, htmlTag } from 'hexo-util';
+import type Hexo from '../../hexo';
 
 /**
  * Url for tag
@@ -6,7 +7,7 @@ import { url_for, htmlTag } from 'hexo-util';
  * Syntax:
  *   {% url_for text path [relative] %}
  */
-export = ctx => {
+export = (ctx: Hexo) => {
   return function urlForTag([text, path, relative]) {
     const url = url_for.call(ctx, path, relative ? { relative: relative !== 'false' } : undefined);
     const attrs = {
diff --git a/lib/theme/index.ts b/lib/theme/index.ts
index d37cd281b5..aff5a74711 100644
--- a/lib/theme/index.ts
+++ b/lib/theme/index.ts
@@ -6,14 +6,16 @@ import { config } from './processors/config';
 import { i18n } from './processors/i18n';
 import { source } from './processors/source';
 import { view } from './processors/view';
+import type Hexo from '../hexo';
 
 class Theme extends Box {
   public config: any;
   public views: any;
-  public i18n: any;
+  public i18n: I18n;
   public View: any;
+  public processors: any[];
 
-  constructor(ctx, options?) {
+  constructor(ctx: Hexo, options?) {
     super(ctx, ctx.theme_dir, options);
 
     this.config = {};
@@ -46,7 +48,7 @@ class Theme extends Box {
     _View.prototype._helper = ctx.extend.helper;
   }
 
-  getView(path) {
+  getView(path: string) {
     // Replace backslashes on Windows
     path = path.replace(/\\/g, '/');
 
@@ -63,7 +65,7 @@ class Theme extends Box {
     return views[Object.keys(views)[0]];
   }
 
-  setView(path, data) {
+  setView(path: string, data) {
     const ext = extname(path);
     const name = path.substring(0, path.length - ext.length);
     this.views[name] = this.views[name] || {};
@@ -72,7 +74,7 @@ class Theme extends Box {
     views[ext] = new this.View(path, data);
   }
 
-  removeView(path) {
+  removeView(path: string) {
     const ext = extname(path);
     const name = path.substring(0, path.length - ext.length);
     const views = this.views[name];
diff --git a/lib/theme/processors/config.ts b/lib/theme/processors/config.ts
index 64f65e2c28..c37f3ed13a 100644
--- a/lib/theme/processors/config.ts
+++ b/lib/theme/processors/config.ts
@@ -1,13 +1,15 @@
 import { Pattern } from 'hexo-util';
+import type { _File } from '../../box';
+import Theme from '..';
 
-function process(file) {
+function process(file: _File) {
   if (file.type === 'delete') {
-    file.box.config = {};
+    (file.box as Theme).config = {};
     return;
   }
 
   return file.render().then(result => {
-    file.box.config = result;
+    (file.box as Theme).config = result;
     this.log.debug('Theme config loaded.');
   }).catch(err => {
     this.log.error('Theme config load failed.');
diff --git a/lib/theme/processors/i18n.ts b/lib/theme/processors/i18n.ts
index ce955eb8a4..af2db9be95 100644
--- a/lib/theme/processors/i18n.ts
+++ b/lib/theme/processors/i18n.ts
@@ -1,11 +1,13 @@
 import { Pattern } from 'hexo-util';
 import { extname } from 'path';
+import type { _File } from '../../box';
+import type Theme from '..';
 
-function process(file) {
+function process(file: _File) {
   const { path } = file.params;
   const ext = extname(path);
   const name = path.substring(0, path.length - ext.length);
-  const { i18n } = file.box;
+  const { i18n } = (file.box as Theme);
 
   if (file.type === 'delete') {
     i18n.remove(name);
diff --git a/lib/theme/processors/source.ts b/lib/theme/processors/source.ts
index 40915fae47..ac8c21a1fe 100644
--- a/lib/theme/processors/source.ts
+++ b/lib/theme/processors/source.ts
@@ -1,7 +1,8 @@
 import { Pattern } from 'hexo-util';
 import * as common from '../../plugins/processor/common';
+import type { _File } from '../../box';
 
-function process(file) {
+function process(file: _File) {
   const Asset = this.model('Asset');
   const id = file.source.substring(this.base_dir.length).replace(/\\/g, '/');
   const { path } = file.params;
diff --git a/lib/theme/processors/view.ts b/lib/theme/processors/view.ts
index c4011564e2..c127d02e7c 100644
--- a/lib/theme/processors/view.ts
+++ b/lib/theme/processors/view.ts
@@ -1,15 +1,17 @@
 import { Pattern } from 'hexo-util';
+import type { _File } from '../../box';
+import type Theme from '..';
 
-function process(file) {
+function process(file: _File) {
   const { path } = file.params;
 
   if (file.type === 'delete') {
-    file.box.removeView(path);
+    (file.box as Theme).removeView(path);
     return;
   }
 
   return file.read().then(result => {
-    file.box.setView(path, result);
+    (file.box as Theme).setView(path, result);
   });
 }
 
diff --git a/lib/theme/view.ts b/lib/theme/view.ts
index f2b2234d4f..af4c75be62 100644
--- a/lib/theme/view.ts
+++ b/lib/theme/view.ts
@@ -1,8 +1,10 @@
 import { dirname, extname, join } from 'path';
 import { parse as yfm } from 'hexo-front-matter';
 import Promise from 'bluebird';
+import type Theme from '.';
+import type Render from '../hexo/render';
 
-const assignIn = (target, ...sources) => {
+const assignIn = (target: any, ...sources: any[]) => {
   const length = sources.length;
 
   if (length < 1 || target == null) return target;
@@ -21,18 +23,16 @@ class Options {
 }
 
 class View {
-  public path: any;
+  public path: string;
   public source: any;
-  public _theme: any;
+  public _theme: Theme;
   public data: any;
   public _compiled: any;
   public _compiledSync: any;
   public _helper: any;
-  public _render: any;
-  public layout: any;
-  public _content: any;
+  public _render: Render;
 
-  constructor(path, data) {
+  constructor(path: string, data) {
     this.path = path;
     this.source = join(this._theme.base, 'layout', path);
     this.data = typeof data === 'string' ? yfm(data) : data;
@@ -106,7 +106,7 @@ class View {
     return locals;
   }
 
-  _resolveLayout(name) {
+  _resolveLayout(name: string) {
     // Relative path
     const layoutPath = join(dirname(this.path), name);
     let layoutView = this._theme.getView(layoutPath);
@@ -128,7 +128,7 @@ class View {
       text: this.data._content
     };
 
-    function buildFilterArguments(result) {
+    function buildFilterArguments(result: any): [string, any, any] {
       const output = render.getOutput(ext) || ext;
       return [
         `after_render:${output}`,
diff --git a/lib/types.ts b/lib/types.ts
new file mode 100644
index 0000000000..ea6313c253
--- /dev/null
+++ b/lib/types.ts
@@ -0,0 +1 @@
+type NodeJSLikeCallback<R, E = any> = (err: E, result?: R) => void
diff --git a/package.json b/package.json
index a9681ab722..f9cfc7ad34 100644
--- a/package.json
+++ b/package.json
@@ -66,12 +66,13 @@
     "warehouse": "^5.0.0"
   },
   "devDependencies": {
-    "0x": "^5.1.2",
     "@types/bluebird": "^3.5.37",
     "@types/node": "^18.11.8",
     "@types/nunjucks": "^3.2.2",
+    "@types/text-table": "^0.2.4",
     "@typescript-eslint/eslint-plugin": "^5.41.0",
     "@typescript-eslint/parser": "^5.41.0",
+    "0x": "^5.1.2",
     "c8": "^8.0.0",
     "chai": "^4.3.6",
     "cheerio": "0.22.0",
diff --git a/test/scripts/box/box.js b/test/scripts/box/box.js
index 71548cceeb..4aaebd8698 100644
--- a/test/scripts/box/box.js
+++ b/test/scripts/box/box.js
@@ -9,7 +9,7 @@ const { spy, match, assert: sinonAssert } = require('sinon');
 describe('Box', () => {
   const Hexo = require('../../../dist/hexo');
   const baseDir = join(__dirname, 'box_tmp');
-  const Box = require('../../../dist/box');
+  const Box = require('../../../dist/box').default;
 
   const newBox = (path, config) => {
     const hexo = new Hexo(baseDir, { silent: true });
diff --git a/test/scripts/box/file.js b/test/scripts/box/file.js
index e019d913cc..f2fe533b4c 100644
--- a/test/scripts/box/file.js
+++ b/test/scripts/box/file.js
@@ -7,7 +7,7 @@ const { load } = require('js-yaml');
 describe('File', () => {
   const Hexo = require('../../../dist/hexo');
   const hexo = new Hexo(__dirname);
-  const Box = require('../../../dist/box');
+  const Box = require('../../../dist/box').default;
   const box = new Box(hexo, join(hexo.base_dir, 'file_test'));
   const { File } = box;
 
diff --git a/test/scripts/extend/renderer.js b/test/scripts/extend/renderer.js
index 44327d0cb7..8cb8131251 100644
--- a/test/scripts/extend/renderer.js
+++ b/test/scripts/extend/renderer.js
@@ -1,7 +1,7 @@
 'use strict';
 
 describe('Renderer', () => {
-  const Renderer = require('../../../dist/extend/renderer');
+  const Renderer = require('../../../dist/extend/renderer').default;
 
   it('register()', () => {
     const r = new Renderer();