unenv

unenv is a framework agnostic system that allows converting JavaScript code to be platform agnostic and working in any environment including Browsers, Workers, Node.js or pure JavaScript runtime.

Install

# Using npm
npm i -D unenv

# Using yarn
yarn add --dev unenv

# Using pnpm
pnpm add -D unenv

Usage

Using env utility and built-in presets (and nodeless), unenv will provide an abstract configuration that can be used in building pipelines (rollup.js, webpack, etc.).

import { env, node, nodeless } from "unenv";

const { alias, inject, polyfill, external } = env(...presets);

Presets

node

Suitable to convert universal libraries working in Node.js. (preset)

• Add supports for global fetch API
• Set Node.js built-ins as externals

nodeless

Using this preset, we can convert a code that is depending on Node.js to work anywhere else.

Built-in Node.js modules

unenv provides a replacement for all Node.js built-ins for cross-platform compatiblity.

Module	Status	Source
node:assert	Mocked	-
node:async_hooks	Polyfilled	unenv/node/async_hooks
node:buffer	Polyfilled	unenv/node/buffer
node:child_process	Mocked	-
node:cluster	Mocked	-
node:console	Mocked	-
node:constants	Mocked	-
node:crypto	Polyfilled	unenv/node/crypto
node:dgram	Mocked	-
node:diagnostics_channel	Mocked	-
node:dns	Mocked	-
node:domain	Mocked	-
node:events	Polyfilled	unenv/node/events
node:fs	Polyfilled	unenv/node/fs
node:fs/promises	Polyfilled	unenv/node/fs/promises
node:http2	Mocked	-
node:http	Polyfilled	unenv/node/http
node:https	Mocked	-
node:inspector	Mocked	-
node:module	Mocked	-
node:net	Polyfilled	unenv/node/net
node:os	Mocked	-
node:path	Polyfilled	unenv/node/path
node:perf_hooks	Mocked	-
node:process	Polyfilled	unenv/node/process
node:punycode	Mocked	-
node:querystring	Mocked	-
node:readline	Mocked	-
node:repl	Mocked	-
node:stream	Polyfilled	unenv/node/stream
node:stream/consumers	Mocked	unenv/node/stream/consumers
node:stream/promises	Mocked	unenv/node/stream/promises
node:stream/web	Native	unenv/node/stream/web
node:string_decoder	Mocked	-
node:sys	Mocked	-
node:timers	Mocked	-
node:timers/promises	Mocked	-
node:tls	Mocked	-
node:trace_events	Mocked	-
node:tty	Mocked	-
node:url	Polyfilled	unenv/node/url
node:util	Polyfilled	unenv/node/util
node:util/types	Polyfilled	unenv/node/util/types
node:v8	Mocked	-
node:vm	Mocked	-
node:wasi	Mocked	-
node:worker_threads	Mocked	-
node:zlib	Mocked	-

npm packages

unenv provides a replacement for common npm packages for cross platform compatibility.

Package	Status	Source
npm/consola	Use native console	unenv/runtime/npm/consola
npm/cross-fetch	Use native fetch	unenv/runtime/npm/cross-fetch
npm/debug	Mocked with console.debug	unenv/runtime/npm/debug
npm/fsevents	Mocked	unenv/runtime/npm/fsevents
npm/inherits	Inlined	unenv/runtime/npm/inherits
npm/mime-db	Minimized	unenv/runtime/npm/mime-db
npm/mime	Minimized	unenv/runtime/npm/mime
npm/node-fetch	Use native fetch	unenv/runtime/npm/node-fetch
npm/whatwg-url	Use native URL	unenv/runtime/npm/whatwg-url

Auto-mocking proxy

import MockProxy from "unenv/runtime/mock/proxy";

console.log(MockProxy().foo.bar()[0]);

Above package doesn’t work outside of Node.js and neither we need any platform specific logic! When aliasing os to mock/proxy-cjs, it will be auto mocked using a Proxy Object which can be recursively traversed like an Object, called like a Function, Iterated like an Array, or instantiated like a Class.

We use this proxy for auto mocking unimplemented internals. Imagine a package does this:

const os = require("os");
if (os.platform() === "windows") {
  /* do some fix */
}
module.exports = () => "Hello world";

By aliasing os to unenv/runtime/mock/proxy-cjs, code will be compatible with other platforms.

Other polyfills

Please check ./src/runtime to discover other polyfills.

License

MIT