# 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. Latest version **1.10.0** (published 2024-07-16) · MIT license · 0 weekly downloads ## Install ```sh npm install unenv pnpm add unenv yarn add unenv bun add unenv ``` ## Health **Score 45/100 (D)** — status: abandoned. Positive: has types; esm support; no vulnerabilities; high maintenance score; high quality score. Warnings: low downloads. Negative: abandoned. ## Facts | | | |---|---| | Version | 1.10.0 | | Published | 2024-07-16 | | First published | 2021-04-21 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Dependencies | 5 | | Unpacked size | 421.8 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 768 | | Maintainers | pi0 | ## Links - npm: https://www.npmjs.com/package/unenv - Repository: https://github.com/unjs/unenv - Homepage: https://github.com/unjs/unenv#readme - Issues: https://github.com/unjs/unenv/issues - npm.io page: https://npm.io/package/unenv ## Dependencies (5) - [defu](https://npm.io/package/defu.md) ^6.1.4 - [mime](https://npm.io/package/mime.md) ^3.0.0 - [pathe](https://npm.io/package/pathe.md) ^1.1.2 - [consola](https://npm.io/package/consola.md) ^3.2.3 - [node-fetch-native](https://npm.io/package/node-fetch-native.md) ^1.6.4 ## Recent versions - 1.10.0 (latest) — 2024-07-16 - 2.0.0-rc.24 (rc) — 2025-10-29 - 2.0.0-rc.23 — 2025-10-28 - 2.0.0-rc.22 — 2025-10-23 - 2.0.0-rc.21 — 2025-09-04 - 2.0.0-rc.20 — 2025-09-02 - 2.0.0-rc.19 — 2025-07-26 - 2.0.0-rc.18 — 2025-06-25 - 2.0.0-rc.17 — 2025-05-12 - 2.0.0-rc.16 — 2025-05-12 - 2.0.0-rc.15 — 2025-03-17 - 2.0.0-rc.14 — 2025-03-08 - 2.0.0-rc.13 — 2025-03-08 - 2.0.0-rc.12 — 2025-03-04 - 2.0.0-rc.11 — 2025-03-04 - … 68 more at https://npm.io/package/unenv/versions ## README # 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](https://github.com/unjs/unenv) for latest development. ## Install ```bash # 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](https://rollupjs.org), [webpack](https://webpack.js.org), etc.). ```js 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)](./src/presets/node.ts) Suitable to convert universal libraries working in Node.js. - Add supports for global [`fetch` API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API) - Set Node.js built-ins as externals ```js import { env, nodeless } from "unenv"; const envConfig = env(node, {}); ``` ### `nodeless` [(view source)](./src/presets/nodeless.ts) Suitable to transform libraries made for Node.js to run in other JavaScript runtimes. ```js import { env, nodeless } from "unenv"; const envConfig = env(nodeless, {}); ``` ### `deno` [(view source)](./src/presets/deno.ts) This preset can be used to extend `nodeless` to use Deno's Node.js API Compatibility ([docs](https://docs.deno.com/runtime/manual/node/compatibility), [docs](https://docs.deno.com/deploy/api/runtime-node)). > [!WARNING] > This preset is **experimental** and behavior might change! ```js import { env, nodeless, deno } from "unenv"; const envConfig = env(nodeless, deno, {}); ``` ### `cloudflare` [(view source)](./src/presets/cloudflare.ts) This preset can be used to extend `nodeless` to use [Cloudflare Worker](https://workers.cloudflare.com/) Node.js API Compatibility ([docs](https://developers.cloudflare.com/workers/runtime-apis/nodejs/)). > [!WARNING] > This preset is **experimental** and behavior might change! > [!NOTE] > Make sure to enable [`nodejs_compat`](https://developers.cloudflare.com/workers/configuration/compatibility-dates/#nodejs-compatibility-flag) compatibility flag. ```js import { env, nodeless, cloudflare } from "unenv"; const envConfig = env(nodeless, cloudflare, {}); ``` ### `vercel` This preset can be used to extend `nodeless` to use [Vercel Edge](https://vercel.com/docs/functions/edge-functions/edge-runtime) Node.js API Compatibility ([docs](https://vercel.com/docs/functions/edge-functions/edge-runtime#compatible-node.js-modules)). > [!WARNING] > This preset is **experimental** and behavior might change! ```js 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. | Module | Status | Source | | --------------------------------------------------------------------------- | ---------- | ------------------------------------------------------------------ | | [node:assert](https://nodejs.org/api/assert.html) | Mocked | - | | [node:async_hooks](https://nodejs.org/api/async_hooks.html) | Polyfilled | [unenv/node/async_hooks](./src/runtime/node/async_hooks) | | [node:buffer](https://nodejs.org/api/buffer.html) | Polyfilled | [unenv/node/buffer](./src/runtime/node/buffer) | | [node:child_process](https://nodejs.org/api/child_process.html) | Mocked | - | | [node:cluster](https://nodejs.org/api/cluster.html) | Mocked | - | | [node:console](https://nodejs.org/api/console.html) | Mocked | - | | [node:constants](https://nodejs.org/api/constants.html) | Mocked | - | | [node:crypto](https://nodejs.org/api/crypto.html) | Polyfilled | [unenv/node/crypto](./src/runtime/node/crypto) | | [node:dgram](https://nodejs.org/api/dgram.html) | Mocked | - | | [node:diagnostics_channel](https://nodejs.org/api/diagnostics_channel.html) | Mocked | - | | [node:dns](https://nodejs.org/api/dns.html) | Mocked | - | | [node:domain](https://nodejs.org/api/domain.html) | Mocked | - | | [node:events](https://nodejs.org/api/events.html) | Polyfilled | [unenv/node/events](./src/runtime/node/events) | | [node:fs](https://nodejs.org/api/fs.html) | Polyfilled | [unenv/node/fs](./src/runtime/node/fs) | | [node:fs/promises](https://nodejs.org/api/fs/promises.html) | Polyfilled | [unenv/node/fs/promises](./src/runtime/node/fs/promises) | | [node:http2](https://nodejs.org/api/http2.html) | Mocked | - | | [node:http](https://nodejs.org/api/http.html) | Polyfilled | [unenv/node/http](./src/runtime/node/http) | | [node:https](https://nodejs.org/api/https.html) | Polyfilled | [unenv/node/https](./src/runtime/node/https) | | [node:inspector](https://nodejs.org/api/inspector.html) | Mocked | - | | [node:module](https://nodejs.org/api/module.html) | Polyfilled | [unenv/node/module](./src/runtime/node/module) - | | [node:net](https://nodejs.org/api/net.html) | Polyfilled | [unenv/node/net](./src/runtime/node/net) | | [node:os](https://nodejs.org/api/os.html) | Mocked | - | | [node:path](https://nodejs.org/api/path.html) | Polyfilled | [unenv/node/path](./src/runtime/node/path) | | [node:perf_hooks](https://nodejs.org/api/perf_hooks.html) | Mocked | - | | [node:process](https://nodejs.org/api/process.html) | Polyfilled | [unenv/node/process](./src/runtime/node/process) | | [node:punycode](https://nodejs.org/api/punycode.html) | Mocked | - | | [node:querystring](https://nodejs.org/api/querystring.html) | Mocked | - | | [node:readline](https://nodejs.org/api/readline.html) | Mocked | - | | [node:repl](https://nodejs.org/api/repl.html) | Mocked | - | | [node:stream](https://nodejs.org/api/stream.html) | Polyfilled | [unenv/node/stream](./src/runtime/node/stream) | | [node:stream/consumers](https://nodejs.org/api/stream.html) | Mocked | [unenv/node/stream/consumers](./src/runtime/node/stream/consumers) | | [node:stream/promises](https://nodejs.org/api/stream.html) | Mocked | [unenv/node/stream/promises](./src/runtime/node/stream/promises) | | [node:stream/web](https://nodejs.org/api/stream.html) | Native | [unenv/node/stream/web](./src/runtime/node/stream/web) | | [node:string_decoder](https://nodejs.org/api/string_decoder.html) | Polyfilled | [unenv/node/string_decoder](./src/runtime/node/string_decoder) | | [node:sys](https://nodejs.org/api/sys.html) | Mocked | - | | [node:timers](https://nodejs.org/api/timers.html) | Mocked | - | | [node:timers/promises](https://nodejs.org/api/timers.html) | Mocked | - | | [node:tls](https://nodejs.org/api/tls.html) | Mocked | - | | [node:trace_events](https://nodejs.org/api/trace_events.html) | Mocked | - | | [node:tty](https://nodejs.org/api/tty.html) | Mocked | - | | [node:url](https://nodejs.org/api/url.html) | Polyfilled | [unenv/node/url](./src/runtime/node/url) | | [node:util](https://nodejs.org/api/util.html) | Polyfilled | [unenv/node/util](./src/runtime/node/util) | | [node:util/types](https://nodejs.org/api/util.html) | Polyfilled | [unenv/node/util/types](./src/runtime/node/util/types) | | [node:v8](https://nodejs.org/api/v8.html) | Mocked | - | | [node:vm](https://nodejs.org/api/vm.html) | Mocked | - | | [node:wasi](https://nodejs.org/api/wasi.html) | Mocked | - | | [node:worker_threads](https://nodejs.org/api/worker_threads.html) | Mocked | - | | [node:zlib](https://nodejs.org/api/zlib.html) | Mocked | - | ## npm packages `unenv` provides a replacement for common npm packages for cross platform compatibility. | Package | Status | Source | | ----------------------------------------------------------- | --------------------------- | ----------------------------------------------------------------- | | [npm/consola](https://www.npmjs.com/package/consola) | Use native `console` | [unenv/runtime/npm/consola](./src/runtime/npm/consola.ts) | | [npm/cross-fetch](https://www.npmjs.com/package/node-fetch) | Use native `fetch` | [unenv/runtime/npm/cross-fetch](./src/runtime/npm/cross-fetch.ts) | | [npm/debug](https://www.npmjs.com/package/debug) | Mocked with `console.debug` | [unenv/runtime/npm/debug](./src/runtime/npm/debug.ts) | | [npm/fsevents](https://www.npmjs.com/package/fsevents) | Mocked | [unenv/runtime/npm/fsevents](./src/runtime/npm/fsevents.ts) | | [npm/inherits](https://www.npmjs.com/package/inherits) | Inlined | [unenv/runtime/npm/inherits](./src/runtime/npm/inherits.ts) | | [npm/mime-db](https://www.npmjs.com/package/mime-db) | Minimized | [unenv/runtime/npm/mime-db](./src/runtime/npm/mime-db.ts) | | [npm/mime](https://www.npmjs.com/package/mime) | Minimized | [unenv/runtime/npm/mime](./src/runtime/npm/mime.ts) | | [npm/node-fetch](https://www.npmjs.com/package/node-fetch) | Use native `fetch` | [unenv/runtime/npm/node-fetch](./src/runtime/npm/node-fetch.ts) | | [npm/whatwg-url](https://www.npmjs.com/package/whatwg-url) | Use native `URL` | [unenv/runtime/npm/whatwg-url](./src/runtime/npm/whatwg-url.ts) | ## Auto-mocking proxy ```js 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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy) 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: ```js 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](./src/runtime). ## License MIT --- _Source: https://npm.io/package/unenv · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._