feat: 🎸 implement initial version of writeFile() method

src/fsa-to-node/FsaNodeFs.ts

@@ -10,6 +10,8 @@ import {
   getAppendFileOptsAndCb,
   getStatOptsAndCb,
   getRealpathOptsAndCb,
+  writeFileDefaults,
+  getWriteFileOptions,
 } from '../node/options';
 import {
   createError,
@@ -125,11 +127,11 @@ export class FsaNodeFs implements FsCallbackApi, FsCommonObjects {
     return file;
   }
 
-  private async getFileById(id: misc.TFileId, funcName?: string): Promise<fsa.IFileSystemFileHandle> {
+  private async getFileById(id: misc.TFileId, funcName?: string, create?: boolean): Promise<fsa.IFileSystemFileHandle> {
     if (typeof id === 'number') return (await this.getFileByFd(id, funcName)).file;
     const filename = pathToFilename(id);
     const [folder, name] = pathToLocation(filename);
-    return await this.getFile(folder, name, funcName);
+    return await this.getFile(folder, name, funcName, create);
   }
 
   private async getFileByIdOrCreate(id: misc.TFileId, funcName?: string): Promise<fsa.IFileSystemFileHandle> {
@@ -235,20 +237,30 @@ export class FsaNodeFs implements FsCallbackApi, FsCommonObjects {
     );
   };
 
-  writeFile(id: misc.TFileId, data: misc.TData, callback: misc.TCallback<void>);
-  writeFile(
-    id: misc.TFileId,
-    data: misc.TData,
-    options: opts.IWriteFileOptions | string,
-    callback: misc.TCallback<void>,
-  );
-  writeFile(
+  public readonly writeFile: FsCallbackApi['writeFile'] = (
     id: misc.TFileId,
     data: misc.TData,
     a: misc.TCallback<void> | opts.IWriteFileOptions | string,
     b?: misc.TCallback<void>,
-  ) {
-    throw new Error('Not implemented');
+  ): void => {
+    let options: opts.IWriteFileOptions | string = a as opts.IWriteFileOptions;
+    let callback: misc.TCallback<void> | undefined = b;
+    if (typeof a === 'function') {
+      options = writeFileDefaults;
+      callback = a;
+    }
+    const cb = validateCallback(callback);
+    const opts = getWriteFileOptions(options);
+    const flagsNum = flagsToNumber(opts.flag);
+    const modeNum = modeToNumber(opts.mode);
+    const buf = dataToBuffer(data, opts.encoding);
+    (async () => {
+      const createIfMissing = !!(flagsNum & FLAG.O_CREAT);
+      const file = await this.getFileById(id, 'writeFile', createIfMissing);
+      const writable = await file.createWritable({ keepExistingData: false });
+      await writable.write(buf);
+      await writable.close();
+    })().then(() => cb(null), error => cb(error));
   }
 
   public readonly copyFile: FsCallbackApi['copyFile'] = (src: misc.PathLike, dest: misc.PathLike, a, b?): void => {
@@ -316,14 +328,6 @@ export class FsaNodeFs implements FsCallbackApi, FsCommonObjects {
     callback(null, strToEncoding(pathFilename, opts.encoding));
   };
 
-  public readonly lstat: FsCallbackApi['lstat'] = (
-    path: misc.PathLike,
-    a: misc.TCallback<misc.IStats> | opts.IStatOptions,
-    b?: misc.TCallback<misc.IStats>,
-  ): void => {
-    this.stat(path, <any>a, <any>b);
-  };
-
   public readonly stat: FsCallbackApi['stat'] = (
     path: misc.PathLike,
     a: misc.TCallback<misc.IStats> | opts.IStatOptions,
@@ -341,6 +345,8 @@ export class FsaNodeFs implements FsCallbackApi, FsCommonObjects {
     );
   };
 
+  public readonly lstat: FsCallbackApi['lstat'] = this.stat;
+
   public readonly fstat: FsCallbackApi['fstat'] = (
     fd: number,
     a: misc.TCallback<misc.IStats> | opts.IStatOptions,

src/fsa-to-node/__tests__/FsaNodeFs.test.ts

@@ -560,3 +560,22 @@ describe('.copyFile()', () => {
     });
   });
 });
+
+describe('.writeFile()', () => {
+  test('can create a new file', async () => {
+    const { fs, mfs } = setup({ folder: { file: 'test' }, 'empty-folder': null, 'f.html': 'test' });
+    const res = await new Promise<void>((resolve, reject) => {
+      fs.writeFile('/folder/foo', 'bar', (error) => {
+        if (error) reject(error);
+        else resolve();
+      });
+    });
+    expect(res).toBe(undefined);
+    expect(mfs.__vol.toJSON()).toStrictEqual({
+      '/mountpoint/folder/file': 'test',
+      '/mountpoint/folder/foo': 'bar',
+      '/mountpoint/empty-folder': null,
+      '/mountpoint/f.html': 'test',
+    });
+  });
+});

src/node/options.ts

@@ -102,3 +102,10 @@ export const getStatOptsAndCb: (
 const realpathDefaults: opts.IReadFileOptions = optsDefaults;
 export const getRealpathOptions = optsGenerator<opts.IRealpathOptions>(realpathDefaults);
 export const getRealpathOptsAndCb = optsAndCbGenerator<opts.IRealpathOptions, misc.TDataOut>(getRealpathOptions);
+
+export const writeFileDefaults: opts.IWriteFileOptions = {
+  encoding: 'utf8',
+  mode: MODE.DEFAULT,
+  flag: FLAGS[FLAGS.w],
+};
+export const getWriteFileOptions = optsGenerator<opts.IWriteFileOptions>(writeFileDefaults);

src/volume.ts

@@ -25,14 +25,14 @@ import {
   getRmOptsAndCb,
   getRmdirOptions,
   optsAndCbGenerator,
-  optsDefaults,
-  optsGenerator,
   getAppendFileOptsAndCb,
   getAppendFileOpts,
   getStatOptsAndCb,
   getStatOptions,
   getRealpathOptsAndCb,
   getRealpathOptions,
+  getWriteFileOptions,
+  writeFileDefaults,
 } from './node/options';
 import {
   validateCallback,
@@ -116,17 +116,6 @@ export type TFlagsCopy =
 
 // ---------------------------------------- Options
 
-// General options with optional `encoding` property that most commands accept.
-
-// Options for `fs.writeFile` and `fs.writeFileSync`
-export interface IWriteFileOptions extends opts.IFileOptions {}
-const writeFileDefaults: IWriteFileOptions = {
-  encoding: 'utf8',
-  mode: MODE.DEFAULT,
-  flag: FLAGS[FLAGS.w],
-};
-const getWriteFileOptions = optsGenerator<IWriteFileOptions>(writeFileDefaults);
-
 // Options for `fs.appendFile` and `fs.appendFileSync`
 export interface IAppendFileOptions extends opts.IFileOptions {}
 
@@ -1017,7 +1006,7 @@ export class Volume {
     }
   }
 
-  writeFileSync(id: TFileId, data: TData, options?: IWriteFileOptions) {
+  writeFileSync(id: TFileId, data: TData, options?: opts.IWriteFileOptions) {
     const opts = getWriteFileOptions(options);
     const flagsNum = flagsToNumber(opts.flag);
     const modeNum = modeToNumber(opts.mode);
@@ -1026,18 +1015,15 @@ export class Volume {
   }
 
   writeFile(id: TFileId, data: TData, callback: TCallback<void>);
-  writeFile(id: TFileId, data: TData, options: IWriteFileOptions | string, callback: TCallback<void>);
-  writeFile(id: TFileId, data: TData, a: TCallback<void> | IWriteFileOptions | string, b?: TCallback<void>) {
-    let options: IWriteFileOptions | string = a as IWriteFileOptions;
+  writeFile(id: TFileId, data: TData, options: opts.IWriteFileOptions | string, callback: TCallback<void>);
+  writeFile(id: TFileId, data: TData, a: TCallback<void> | opts.IWriteFileOptions | string, b?: TCallback<void>) {
+    let options: opts.IWriteFileOptions | string = a as opts.IWriteFileOptions;
     let callback: TCallback<void> | undefined = b;
-
     if (typeof a === 'function') {
       options = writeFileDefaults;
       callback = a;
     }
-
     const cb = validateCallback(callback);
-
     const opts = getWriteFileOptions(options);
     const flagsNum = flagsToNumber(opts.flag);
     const modeNum = modeToNumber(opts.mode);