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In-memory file-system withNode'sfs API.

• 100% of Node'sfs API implemented, seeAPI Status
• Stores files in memory, inBuffers
• Throws same* errors as Node.js
• Has concept ofi-nodes
• Implementshard links
• Implementssoft links (aka symlinks, symbolic links)
• More testing coming soon*
• Permissions may* be implemented in the future
• Can be used in browser, seememfs-webpack

npm install --save memfs

import{fs}from'memfs';fs.writeFileSync('/hello.txt','World!');fs.readFileSync('/hello.txt','utf8');// World!

Create a file system from a plain JSON:

import{fs,vol}from'memfs';constjson={'./README.md':'1','./src/index.js':'2','./node_modules/debug/index.js':'3',};vol.fromJSON(json,'/app');fs.readFileSync('/app/README.md','utf8');// 1vol.readFileSync('/app/src/index.js','utf8');// 2

Export to JSON:

vol.writeFileSync('/script.sh','sudo rm -rf *');vol.toJSON();// {"/script.sh": "sudo rm -rf *"}

Use it for testing:

vol.writeFileSync('/foo','bar');expect(vol.toJSON()).toEqual({"/foo":"bar"});

Create as many filesystem volumes as you need:

import{Volume}from'memfs';constvol=Volume.fromJSON({'/foo':'bar'});vol.readFileSync('/foo');// barconstvol2=Volume.fromJSON({'/foo':'bar 2'});vol2.readFileSync('/foo');// bar 2

Usememfs together withunionfs to create one filesystemfrom your in-memory volumes and the real disk filesystem:

import*asfsfrom'fs';import{ufs}from'unionfs';ufs.use(fs).use(vol);ufs.readFileSync('/foo');// bar

Usefs-monkey to monkey-patch Node'srequire function:

import{patchRequire}from'fs-monkey';vol.writeFileSync('/index.js','console.log("hi world")');patchRequire(vol);require('/index');// hi world

• Reference
• Relative paths
• API status

• spyfs - spies on filesystem actions
• unionfs - creates a union of multiple filesystem volumes
• linkfs - redirects filesystem paths
• fs-monkey - monkey-patches Node'sfs module andrequire function
• libfs - real filesystem (that executes UNIX system calls) implemented in JavaScript

This package depends on the following Node modules:buffer,events,streams,path.

It also usesprocess andsetImmediate globals, but mocks them, if notavailable.

Unlicense - public domain.