feat: 🎸 improve read stream interfaces

src/fsa-to-node/FsaNodeWriteStream copy.ts

@@ -0,0 +1,25 @@
+import { Readable } from 'stream';
+import type { IReadStream } from '../node/types/misc';
+
+export class FsaNodeReadStream extends Readable implements IReadStream {
+  public constructor() {
+    super();
+  }
+
+  // -------------------------------------------------------------- IReadStream
+  public get bytesRead(): number {
+    throw new Error('Method not implemented.');
+  }
+
+  public get path(): string | Buffer {
+    throw new Error('Method not implemented.');
+  }
+
+  public get pending(): boolean {
+    throw new Error('Method not implemented.');
+  }
+
+  // ----------------------------------------------------------------- Readable
+
+  _read(size: number) {}
+}

src/index.ts

@@ -5,14 +5,14 @@ import {
   StatWatcher,
   FSWatcher,
   toUnixTimestamp,
-  IReadStream,
   IWriteStream,
   DirectoryJSON,
   NestedDirectoryJSON,
 } from './volume';
 const { fsSyncMethods, fsAsyncMethods } = require('fs-monkey/lib/util/lists');
 import { constants } from './constants';
 import type { FsPromisesApi } from './node/types';
+import type * as misc from './node/types/misc';
 const { F_OK, R_OK, W_OK, X_OK } = constants;
 
 export { DirectoryJSON, NestedDirectoryJSON };
@@ -27,7 +27,7 @@ export interface IFs extends _Volume {
   Dirent: new (...args) => Dirent;
   StatWatcher: new () => StatWatcher;
   FSWatcher: new () => FSWatcher;
-  ReadStream: new (...args) => IReadStream;
+  ReadStream: new (...args) => misc.IReadStream;
   WriteStream: new (...args) => IWriteStream;
   promises: FsPromisesApi;
   _toUnixTimestamp;

src/node/types/misc.ts

@@ -83,11 +83,9 @@ export interface IStatWatcher extends EventEmitter {
 }
 
 export interface IReadStream extends Readable {
-  new (path: PathLike, options: IReadStreamOptions);
-  open();
-  close(callback: TCallback<void>);
   bytesRead: number;
-  path: string;
+  path: string | Buffer;
+  pending: boolean;
 }
 
 export interface IWriteStream extends Writable {

src/node/types/options.ts

@@ -61,13 +61,27 @@ export interface IWatchFileOptions {
 }
 
 export interface IReadStreamOptions {
+  /** Defaults to `'r'`. */
   flags?: TFlags;
-  encoding?: BufferEncoding;
-  fd?: number;
+  /** Defaults to `null`. */
+  encoding?: BufferEncoding | null;
+  /** Defaults to `null`. */
+  fd?: number | IFileHandle | null;
+  /** Defaults to 0o666 */
   mode?: TMode;
+  /** Defaults to `true`. */
   autoClose?: boolean;
+  /** Defaults to `true`. */
+  emitClose?: boolean;
   start?: number;
+  /** Defaults to `Infinity`. */
   end?: number;
+  /** Defaults to `64 * 1024`. */
+  highWaterMark?: number;
+  /** Defaults to `null`. */
+  fs?: object | null;
+  /** Defaults to `null`. */
+  signal?: AbortSignal | null;
 }
 
 export interface IWriteStreamOptions {

src/volume.ts

@@ -11,6 +11,7 @@ import { constants } from './constants';
 import { EventEmitter } from 'events';
 import { TEncodingExtended, TDataOut, strToEncoding, ENCODING_UTF8 } from './encoding';
 import * as util from 'util';
+import * as misc from './node/types/misc';
 import * as opts from './node/types/options';
 import { createPromisesApi } from './node/promises';
 import { ERRSTR, FLAGS, MODE } from './node/constants';
@@ -51,7 +52,7 @@ import {
   getWriteSyncArgs,
 } from './node/util';
 import type { PathLike, symlink } from 'fs';
-import { WritevCallback } from './node/types/callback';
+import { FsCallbackApi, WritevCallback } from './node/types/callback';
 
 const resolveCrossPlatform = pathModule.resolve;
 const {
@@ -128,17 +129,6 @@ export interface IWatchFileOptions {
   interval?: number;
 }
 
-// Options for `fs.createReadStream`
-export interface IReadStreamOptions {
-  flags?: TFlags;
-  encoding?: BufferEncoding;
-  fd?: number;
-  mode?: TMode;
-  autoClose?: boolean;
-  start?: number;
-  end?: number;
-}
-
 // Options for `fs.createWriteStream`
 export interface IWriteStreamOptions {
   flags?: TFlags;
@@ -271,7 +261,7 @@ function flattenJSON(nestedJSON: NestedDirectoryJSON): DirectoryJSON {
 /**
  * `Volume` represents a file system.
  */
-export class Volume {
+export class Volume implements FsCallbackApi {
   static fromJSON(json: DirectoryJSON, cwd?: string): Volume {
     const vol = new Volume();
     vol.fromJSON(json, cwd);
@@ -323,7 +313,7 @@ export class Volume {
   openFiles = 0;
 
   StatWatcher: new () => StatWatcher;
-  ReadStream: new (...args) => IReadStream;
+  ReadStream: new (...args) => misc.IReadStream;
   WriteStream: new (...args) => IWriteStream;
   FSWatcher: new () => FSWatcher;
 
@@ -354,12 +344,12 @@ export class Volume {
       }
     };
 
-    const _ReadStream: new (...args) => IReadStream = FsReadStream as any;
+    const _ReadStream: new (...args) => misc.IReadStream = FsReadStream as any;
     this.ReadStream = class extends _ReadStream {
       constructor(...args) {
         super(self, ...args);
       }
-    } as any as new (...args) => IReadStream;
+    } as any as new (...args) => misc.IReadStream;
 
     const _WriteStream: new (...args) => IWriteStream = FsWriteStream as any;
     this.WriteStream = class extends _WriteStream {
@@ -1900,7 +1890,7 @@ export class Volume {
     }
   }
 
-  createReadStream(path: PathLike, options?: IReadStreamOptions | string): IReadStream {
+  createReadStream(path: misc.PathLike, options?: opts.IReadStreamOptions | string): misc.IReadStream {
     return new this.ReadStream(path, options);
   }
 
@@ -1998,14 +1988,6 @@ export class StatWatcher extends EventEmitter {
 /* tslint:disable no-var-keyword prefer-const */
 // ---------------------------------------- ReadStream
 
-export interface IReadStream extends Readable {
-  new (path: PathLike, options: IReadStreamOptions);
-  open();
-  close(callback: TCallback<void>);
-  bytesRead: number;
-  path: string;
-}
-
 var pool;
 
 function allocNewPool(poolSize) {