memory-fs

What is memory-fs?

The memory-fs npm package is an in-memory filesystem that mimics the Node.js fs module. It allows you to create, read, write, and delete files and directories in memory, which can be useful for testing or when you need a temporary filesystem that does not interact with the actual disk.

What are memory-fs's main functionalities?

Creating and writing files

This feature allows you to create new files and write content to them, similar to fs.writeFileSync in Node.js.

{"const MemoryFS = require('memory-fs');\nconst fs = new MemoryFS();\nfs.writeFileSync('/my-file.txt', 'Hello World');"}

Reading files

This feature allows you to read the contents of files that exist in the in-memory filesystem.

{"const MemoryFS = require('memory-fs');\nconst fs = new MemoryFS();\nfs.writeFileSync('/my-file.txt', 'Hello World');\nconst content = fs.readFileSync('/my-file.txt', 'utf-8');"}

Creating directories

This feature allows you to create directories within the in-memory filesystem.

{"const MemoryFS = require('memory-fs');\nconst fs = new MemoryFS();\nfs.mkdirSync('/my-directory');"}

Deleting files and directories

This feature allows you to delete files and directories from the in-memory filesystem.

{"const MemoryFS = require('memory-fs');\nconst fs = new MemoryFS();\nfs.writeFileSync('/my-file.txt', 'Hello World');\nfs.unlinkSync('/my-file.txt');\nfs.mkdirSync('/my-directory');\nfs.rmdirSync('/my-directory');"}

Other packages similar to memory-fs

memfs

memfs is an in-memory filesystem with the same API as Node.js fs module. It is similar to memory-fs but is actively maintained and has additional features like volume serialization and deserialization.

unionfs

unionfs allows you to create a union of multiple filesystems. While it can work with in-memory filesystems, it can also combine real filesystems and has a broader scope compared to memory-fs.

mock-fs

mock-fs is a library for mocking the Node.js fs module. It allows you to intercept file system operations and provide custom in-memory implementations. It is primarily used for testing purposes and offers a different approach compared to memory-fs.

README

memory-fs

A simple in-memory filesystem. Holds data in a javascript object.

var MemoryFileSystem = require("memory-fs");
var fs = new MemoryFileSystem(); // Optionally pass a javascript object

fs.mkdirpSync("/a/test/dir");
fs.writeFileSync("/a/test/dir/file.txt", "Hello World");
fs.readFileSync("/a/test/dir/file.txt"); // returns Buffer("Hello World")

// Async variants too
fs.unlink("/a/test/dir/file.txt", function(err) {
	// ...
});

fs.readdirSync("/a/test"); // returns ["dir"]
fs.statSync("/a/test/dir").isDirectory(); // returns true
fs.rmdirSync("/a/test/dir");

fs.mkdirpSync("C:\\use\\windows\\style\\paths");

License

Copyright (c) 2012-2014 Tobias Koppers

MIT (http://www.opensource.org/licenses/mit-license.php)