petit-fs

FileSystem on browser using localStorage. Provides node fs compatible interface(Still in progress).

src/vfsUtil.ts is based on typescript harness.

Supporting methods

``ts
existsSync(path: string): boolean;
statSync(path: string): Stats; // Stats only supportes mtime, mtimeMs, isDirectory(), isSymbolicLink(). Time stamps other than mtime may be inaccurate.
utimesSync(path: string, atime: Date, mtime: Date): void;
lstatSync(path: string): Stats;
readdirSync(path: string): string[];
mkdirSync(path: string): void;
rmdirSync(path: string): void;
unlinkSync(path: string): void;
renameSync(src: string, dst: string): void;
symlinkSync(target: string, linkpath: string): void;
realpathSync(path: string): string;
readFileSync(path: string, encoding?: null): Buffer;
readFileSync(path: string, encoding: BufferEncoding): string;
readFileSync(path: string, encoding?: BufferEncoding | null): string | Buffer;
writeFileSync(path: string, data: string | Buffer, encoding?: string | null): void;
writeSync(fd: number, data: string | Buffer, encoding?: string | null): void;
appendFileSync(path: string, data: string | Buffer, encoding?: string | null): void;
watch(path: string, ...opts: any[]): void;
watchFile(path: string, ...opts: any[]): void;
openSync(path: string, mode: string): number; // mode "w" only
closeSync(fd: number): void;
`

Use of RAM disk

fs.mountSync("/mnt/to/","ram") mounts RAM disk instead of localStorage, that have unlimited(Within browser memory) capacity but cleard on unload page.

Representation of files in localStorage

- The key represents the full path of a file.
- The value represents the file content in string
- If the file is a binary file, it is stored in data url.
- Whether the file is binary or text is determined by extension of the file
- src/MIMETypes.js` maps extension to content types. If content type is "text/....", it is regarded as text file
- The key of a directory entry always ends with /
- The value is a JSON with file list and attributes(lastUpdate).