imfs

An in-memory filesystem-like data structure.

Combine this library with immer to support immutability via structural sharing. This is an effective way to store the entire history of a filesystem in a low-memory way, or when you want an in-memory filesystem that works well with React's memoization and reducers.

npm install --save imfs

OR

yarn add imfs

API

There are 4 categories of functions:

1. Volume: A collection of filesystem-like APIs e.g. readFile, writeFile. These functions let you use paths to traverse a hierarchy of file nodes. This is likely the main thing you'll use.
2. Nodes: Lower-level functions for working with file nodes.
3. Entries: A couple small helpers for traversing the volume. Useful when combined with a tree traversal library like tree-visit.
4. path: A subset of node's path API. Only supports Unix-style paths.

Usage

To start, create a volume. In TypeScript, each volume has 2 type parameters: the Data type that will be used to store file data, and optionally any Metadata that should be stored alongside each file and directory.

import { Volume } from 'imfs'

// Initialize a volume where files are stored as strings, with no metadata.
const root = Volume.create<string>()

// Write the string 'Hello, world!' into the file 'e.txt'
Volume.writeFile(root, '/a/b/c/d/e.txt', 'Hello, world!', {
  makeIntermediateDirectories: true,
})

// Read the string stored in 'e.txt'
const data = Volume.readFile(updated, '/a/b/c/d/e.txt')

console.log(data) // $> Hello, world!

For a more realistic filesystem, use a type like Buffer as the Data type (to support binary data), and a type like node's fs.Stats as the Metadata type (for permissions, timestamps, etc).

Volume

• create
• getMetadata
• getNode
• getPathComponents
• makeDirectory
• readDirectory
• readFile
• removeFile
• setMetadata
• setNode
• writeFile

Nodes

• createDirectory
• createFile
• getChild
• getMetadata
• hasChild
• isDirectory
• isFile
• readDirectory

Entries

• createEntry
• getEntries

path

• basename
• dirname
• extname
• join
• normalize
• sep