unenv v1.10.0

unenv

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

!NOTE You are on the legacy (v1) branch. Checkout main branch for latest development.

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, unenv will provide an abstract configuration that can be used in building pipelines (rollup.js, webpack, etc.).

import { env } from "unenv";

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

Note: You can provide as many presets as you want. unenv will merge them internally and the right-most preset has a higher priority.

Presets

node

(view source)

Suitable to convert universal libraries working in Node.js.

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

import { env, nodeless } from "unenv";

const envConfig = env(node, {});

nodeless

(view source)

Suitable to transform libraries made for Node.js to run in other JavaScript runtimes.

import { env, nodeless } from "unenv";

const envConfig = env(nodeless, {});

deno

(view source)

This preset can be used to extend nodeless to use Deno's Node.js API Compatibility (docs, docs).

!WARNING This preset is experimental and behavior might change!

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

const envConfig = env(nodeless, deno, {});

cloudflare

(view source)

This preset can be used to extend nodeless to use Cloudflare Worker Node.js API Compatibility (docs).

!WARNING This preset is experimental and behavior might change!

!NOTE Make sure to enable nodejs_compat compatibility flag.

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

const envConfig = env(nodeless, cloudflare, {});

vercel

This preset can be used to extend nodeless to use Vercel Edge Node.js API Compatibility (docs).

!WARNING This preset is experimental and behavior might change!

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

const envConfig = env(nodeless, vercel, {});

Built-in Node.js modules

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

npm packages

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

Auto-mocking proxy

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

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

The 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("node:os");
if (os.platform() === "windows") {
  /* do some fix */
}
module.exports = function main() {
  return "Hello world"
}

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

Other polyfills

To discover other polyfills, please check ./src/runtime.

License

MIT