fs Monkey

Monkey-patches for file system related things.

Terms

An fs-like object is an object that implements methods that correspond to File System API of Node.js. It is denoted below as the vol parameter.

let vol = {
    readFileSync: () => { /* ... */ },
    // etc...
}

API

• patchFs(vol[, fs]) - rewrites Node's file system module fs with fs-like object
• patchRequire(vol[, Module]) - patches Node's module module to use a give fs-like for module loading

patchFs(vol[, fs])

rewrites Node's file system module fs with fs-like object.

• vol - fs-like object
• fs - a file system to patch, defaults to require('fs')

import {vol} from '../../../memfs/lib';
import {patchFs} from '../index';

vol.fromJSON({'/dir/foo': 'bar'});
patchFs(vol);
console.log(require('fs').readdirSync('/')); // [ 'dir' ]

patchRequire(vol[, Module])

patches Node's module module to use a give fs-like for module loading.

• vol - fs-like object
• Module - a module to patch, defaults to require('module')

Monkey-patches the require function of Node.js, this way you can make Node.js to require modules from your custom file system.

It expects an object with three file system methods implemented that are needed for the require function to work.

patchRequire({
    readFileSync: () => {},
    realpathSync: () => {},
    statSync: () => {},
});

If you want to make Node.js to require your files from memory, you don't need to implement those functions yourself, just use the memfs package:

import {vol} from 'memfs';
import {patchRequire} from 'fs-monkey';

vol.fromJSON({'/foo/bar.js': 'console.log("obi trice");'});
patchRequire(vol);
require('/foo/bar'); // obi trice

Now the require function will only load the files from the vol file system, but not from the actual file system.

If you want the require function to load modules from both file systems, use the unionfs package to combine both file system into a union:

import {vol} from 'memfs';
import {patchRequire} from 'fs-monkey';
import {ufs} from 'unionfs';
import * as fs from 'fs';

vol.fromJSON({'/foo/bar.js': 'console.log("obi trice");'});
ufs
    .use(vol)
    .use(fs);
patchRequire(ufs);
require('/foo/bar.js'); // obi trice

License

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.

In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to http://unlicense.org/