fs-require

fs-require

Create a require() function from any file-system.

Features

• 💞 Works well with memfs!
• 🪄 Resolves implicit entry index and implicit extensions js and json
• 🗺 Resolves relative and absolute paths
• 📍 __dirname & __filename
• 👻 Mocks fs within fsRequire
• 👣 Call stack shows paths with fs-require:// protocol

🙋‍♀️ Why?

Using fs-require with memfs is a great combination for writing tests that interact with the file-system.

Testing functionality that interacts with the file-system can be brittle because they expect a clean slate and can also be dangerous if the path is wrong. Creating a virtual file-system with memfs and testing its contents with fsRequire makes it secure and fast!

👨‍🏫 Usage

import { Volume } from 'memfs'
import { createFsRequire } from 'fs-require'

// Create a virtual fs from JSON
const virtualFs = Volume.fromJSON({
    '/hello-world.js': `
        module.exports = function () {
            return 'Hello world!'
        }
    `
})

// Create fsRequire
const fsRequire = createFsRequire(virtualFs)

// Import virtual module
const helloWorld = fsRequire('/hello-world')

console.log(helloWorld()) // Hello world!

⚙️ API

createFsRequire(fs, options?)

Returns a require(modulePath) function that resolves from the file-system passed in.

fs

Type: FileSystem

Required

The file-system to resolve requires from.

options

options.fs

Type: boolean | FileSystem

Code executed the virtual file-system may require('fs') and this may either pose as a security concern or yield inconsistent results as the virtual file won't not accessible through the actual fs module.

By default require('fs') is shimmed to the file-system passed into createFsRequire.

To disable this behavior and resolve to the real fs module, set this to true.

You can also pass in a different file-system too.

👨‍👩‍👧 Related

• fs-monkey - By the same author of memfs. Patches the global require to access a virtual fs.