unionfs

NOTE: This is a fork of https://www.npmjs.com/package/unionfs, since it has a significant bug, and it hasn't been updated in years. The bug is also not fixed in the upstream github repo though.

Creates a union of multiple fs file systems.

npm install --save unionfs

This module allows you to use multiple objects that have file system fs API at the same time.

1import { ufs } from 'unionfs';
2import { fs as fs1 } from 'memfs';
3import * as fs2 from 'fs';
4
5ufs.use(fs1).use(fs2);
6
7ufs.readFileSync(/* ... */);

Use this module with memfs and linkfs. memfs allows you to create virtual in-memory file system. linkfs allows you to redirect fs paths.

You can also use other fs-like objects.

1import * as fs from 'fs';
2import { Volume } from 'memfs';
3import * as MemoryFileSystem from 'memory-fs';
4import { ufs } from 'unionfs';
5
6const vol1 = Volume.fromJSON({ '/memfs-1': '1' });
7const vol2 = Volume.fromJSON({ '/memfs-2': '2' });
8
9const memoryFs = new MemoryFileSystem();
10memoryFs.writeFileSync('/memory-fs', '3');
11
12ufs.use(fs).use(vol1).use(vol2).use(memoryFs);
13
14console.log(ufs.readFileSync('/memfs-1', 'utf8')); // 1
15console.log(ufs.readFileSync('/memfs-2', 'utf8')); // 2
16console.log(ufs.readFileSync('/memory-fs', 'utf8')); // 3

You can create a Union instance manually:

1import { Union } from 'unionfs';
2
3var ufs1 = new Union();
4ufs1.use(fs).use(vol);
5
6var ufs2 = new Union();
7ufs2.use(fs).use(/*...*/);

License

Unlicense - public domain.