Remove flow type annotations, set up ESLint

.babelrc

@@ -1,7 +1,6 @@
 {
-  "presets": ["@babel/preset-react", "@babel/preset-env", "@babel/preset-flow"],
+  "presets": ["@babel/preset-react", "@babel/preset-env"],
   "plugins": [
-    "@babel/plugin-transform-flow-strip-types",
     "@babel/plugin-proposal-class-properties",
     "@babel/plugin-transform-runtime"
   ]

.github/workflows/lint.yaml

@@ -0,0 +1,22 @@
+name: ESLint
+
+on: [push]
+
+jobs:
+  eslint:
+    name: ESLint
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run ESLint
+        run: npm run eslint

eslint.config.mjs

@@ -0,0 +1,23 @@
+import globals from 'globals';
+import pluginJs from '@eslint/js';
+
+export default [
+  {
+    ignores: ['build/**', 'coverage/**'],
+  },
+
+  {
+    languageOptions: {
+      globals: globals.node,
+    },
+  },
+
+  pluginJs.configs.recommended,
+
+  {
+    files: ['**/__mocks__/**', '**/__tests__/**'],
+    languageOptions: {
+      globals: globals.jest,
+    },
+  },
+];

lib/CommandLineEditor.js

@@ -1,27 +1,27 @@
-// @flow
+//
 export default class CommandLineEditor {
-  _lines: Array<string>;
+  _lines;
 
-  constructor(lines: Array<string>) {
+  constructor(lines) {
     this._lines = lines;
   }
 
-  currentFileContent(): string {
+  currentFileContent() {
     return this._lines.join('\n');
   }
 
-  get(index: number): string {
+  get(index) {
     return this._lines[index];
   }
 
-  remove(index: number) {
+  remove(index) {
     this._lines.splice(index, 1);
   }
 
   /**
    * Insert a line above the specified index
    */
-  insertBefore(index: number, str: string) {
+  insertBefore(index, str) {
     this._lines.splice(index, 0, str);
   }
 }

lib/Configuration.js

@@ -1,4 +1,4 @@
-// @flow
+//
 
 import os from 'os';
 import path from 'path';
@@ -26,16 +26,16 @@ const ENVIRONMENTS = {
   meteor: meteorEnvironment,
 };
 
-function checkConfiguration(config: Object): Array<string> {
+function checkConfiguration(config) {
   const result = validate(config);
 
   return result.messages;
 }
 
-function checkForDeprecatedConfiguration(config: Object): Array<string> {
+function checkForDeprecatedConfiguration(config) {
   const messages = [];
 
-  Object.keys(config).forEach((option: string) => {
+  Object.keys(config).forEach((option) => {
     if (DEPRECATED_CONFIGURATION_OPTIONS.indexOf(option) !== -1) {
       messages.push(
         `Using ${option} to configure ImportJS is deprecated and ` +
@@ -53,7 +53,7 @@ function checkForDeprecatedConfiguration(config: Object): Array<string> {
  * @throws Error if current version is less than the `minimumVersion` defined
  * in config.
  */
-function checkCurrentVersion(minimumVersion: string) {
+function checkCurrentVersion(minimumVersion) {
   if (semver.gte(version(), minimumVersion)) {
     return;
   }
@@ -63,7 +63,7 @@ function checkCurrentVersion(minimumVersion: string) {
   );
 }
 
-function mergedValue(values: Array<any>, key: string, options: Object): any {
+function mergedValue(values, key, options) {
   let mergedResult;
   for (let i = 0; i < values.length; i += 1) {
     let value = values[i];
@@ -95,7 +95,7 @@ function mergedValue(values: Array<any>, key: string, options: Object): any {
 /**
  * returns configuration from a JS file in home directory if it exists, or null
  */
-function loadGlobalJsConfig(): ?Object {
+function loadGlobalJsConfig() {
   for (let i = 0; i < JS_CONFIG_FILES.length; i += 1) {
     const jsConfigFile = JS_CONFIG_FILES[i];
     const globalConfig = FileUtils.readJsFile(
@@ -111,18 +111,15 @@ function loadGlobalJsConfig(): ?Object {
 
 // Class that initializes configuration from a .importjs.js file
 export default class Configuration {
-  pathToCurrentFile: string;
+  pathToCurrentFile;
 
-  messages: Array<string>;
+  messages;
 
-  configs: Array<Object>;
+  configs;
 
-  workingDirectory: string;
+  workingDirectory;
 
-  constructor(
-    pathToCurrentFile: string,
-    workingDirectory: string = process.cwd(),
-  ) {
+  constructor(pathToCurrentFile, workingDirectory = process.cwd()) {
     this.workingDirectory = workingDirectory;
     this.pathToCurrentFile = normalizePath(pathToCurrentFile, workingDirectory);
 
@@ -153,7 +150,7 @@ export default class Configuration {
           pathToCurrentFile: this.pathToCurrentFile,
         });
       }
-      (userConfig.environments || []).forEach((environment: string) => {
+      (userConfig.environments || []).forEach((environment) => {
         const envConfig = ENVIRONMENTS[environment];
         if (envConfig) {
           this.configs.push(envConfig);
@@ -166,24 +163,13 @@ export default class Configuration {
     checkCurrentVersion(this.get('minimumVersion'));
   }
 
-  get(
-    key: string,
-    {
-      pathToImportedModule,
-      moduleName,
-      importStatement,
-    }: {
-      pathToImportedModule?: string,
-      moduleName?: string,
-      importStatement?: string,
-    } = {},
-  ): any {
-    const applyingConfigs = this.configs.filter((config: Object): boolean =>
+  get(key, { pathToImportedModule, moduleName, importStatement } = {}) {
+    const applyingConfigs = this.configs.filter((config) =>
       Object.prototype.hasOwnProperty.call(config, key),
     );
 
     return mergedValue(
-      applyingConfigs.map((config: Object): any => config[key]),
+      applyingConfigs.map((config) => config[key]),
       key,
       {
         pathToImportedModule,
@@ -195,15 +181,15 @@ export default class Configuration {
     );
   }
 
-  loadUserConfig(): ?Object {
+  loadUserConfig() {
     return (
       this.loadLocalJsConfig() ||
       this.loadLocalJsonConfig() ||
       loadGlobalJsConfig()
     );
   }
 
-  loadLocalJsConfig(): ?Object {
+  loadLocalJsConfig() {
     for (let i = 0; i < JS_CONFIG_FILES.length; i += 1) {
       const jsConfigFile = JS_CONFIG_FILES[i];
       const jsConfig = FileUtils.readJsFile(
@@ -227,7 +213,7 @@ export default class Configuration {
     return null;
   }
 
-  loadLocalJsonConfig(): ?Object {
+  loadLocalJsonConfig() {
     const jsonConfig = FileUtils.readJsonFile(
       path.join(this.workingDirectory, JSON_CONFIG_FILE),
     );
@@ -242,7 +228,7 @@ export default class Configuration {
     return null;
   }
 
-  resolveAlias(variableName: string): ?string {
+  resolveAlias(variableName) {
     if (!has(this.get('aliases'), variableName)) {
       return null;
     }
@@ -264,11 +250,10 @@ export default class Configuration {
     return importPath;
   }
 
-  resolveNamedExports(variableName: string): ?JsModule {
+  resolveNamedExports(variableName) {
     const allNamedExports = this.get('namedExports');
     const importPath = Object.keys(allNamedExports).find(
-      (key: string): boolean =>
-        allNamedExports[key].indexOf(variableName) !== -1,
+      (key) => allNamedExports[key].indexOf(variableName) !== -1,
     );
 
     if (!importPath) {

lib/FileUtils.js

@@ -1,8 +1,8 @@
-// @flow
+//
 import fs from 'fs';
 
 export default {
-  readJsonFile(absoluteFilePath: string): ?Object {
+  readJsonFile(absoluteFilePath) {
     if (!fs.existsSync(absoluteFilePath)) {
       return null;
     }
@@ -16,7 +16,7 @@ export default {
     return JSON.parse(contents);
   },
 
-  readJsFile(absoluteFilePath: string): ?Object {
+  readJsFile(absoluteFilePath) {
     if (!fs.existsSync(absoluteFilePath)) {
       return null;
     }