[npm]: https://img.shields.io/npm/v/@rollup/plugin-node-resolve
[npm-url]: https://www.npmjs.com/package/@rollup/plugin-node-resolve
[size]: https://packagephobia.now.sh/badge?p=@rollup/plugin-node-resolve
[size-url]: https://packagephobia.now.sh/result?p=@rollup/plugin-node-resolve
[![npm][npm]][npm-url]
[![size][size]][size-url]
[![libera manifesto](https://img.shields.io/badge/libera-manifesto-lightgrey.svg)](https://liberamanifesto.com)
# @rollup/plugin-node-resolve
🍣 A Rollup plugin which locates modules using the [Node resolution algorithm](https://nodejs.org/api/modules.html#modules_all_together), for using third party modules in `node_modules`
## Requirements
This plugin requires an [LTS](https://github.com/nodejs/Release) Node version (v8.0.0+) and Rollup v1.20.0+.
## Install
Using npm:
```console
npm install @rollup/plugin-node-resolve --save-dev
```
## Usage
Create a `rollup.config.js` [configuration file](https://www.rollupjs.org/guide/en/#configuration-files) and import the plugin:
```js
import resolve from '@rollup/plugin-node-resolve';
export default {
input: 'src/index.js',
output: {
dir: 'output',
format: 'cjs'
},
plugins: [resolve()]
};
```
Then call `rollup` either via the [CLI](https://www.rollupjs.org/guide/en/#command-line-reference) or the [API](https://www.rollupjs.org/guide/en/#javascript-api).
## Options
### `mainFields`
Type: `Array[...String]`
Default: `['module', 'main']`
Valid values: `['browser', 'jsnext', 'module', 'main']`
Specifies the properties to scan within a `package.json`, used to determine the bundle entry point. The order of property names is significant, as the first-found property is used as the resolved entry point. If the array contains `'browser'`, key/values specified in the `package.json` `browser` property will be used.
### `module`
DEPRECATED: use "mainFields" instead
Use `pkg.module` field for ES6 module if possible. This option takes precedence over both "jsnext" and "main" in the list if such are present.
### `jsnext`
DEPRECATED: use "mainFields" instead
Use `pkg['jsnext:main']` if possible, legacy field pointing to ES6 module in third-party libraries, deprecated in favor of `pkg.module`, see: https://github.com/rollup/rollup/wiki/pkg.module. This option takes precedence over "main" in the list if such is present.
### `main`
DEPRECATED: use "mainFields" instead
Use `pkg.main` field or index.js, even if it's not an ES6 module (needs to be converted from CommonJS to ES6), see https://github.com/rollup/rollup-plugin-commonjs.
### `browser`
Type: `Boolean`
Default: `false`
If `true`, instructs the plugin to use the `"browser"` property in `package.json` files to specify alternative files to load for bundling. This is useful when bundling for a browser environment. Alternatively, a value of `'browser'` can be added to the `mainFields` option. If `false`, any `"browser"` properties in package files will be ignored. This option takes precedence over `mainFields`.
### `extensions`
Type: `Array[...String]`
Default: `['.mjs', '.js', '.json', '.node']`
Resolve extensions other than .js in the order specified.
### `preferBuiltins`
Type: `Boolean`
Default: `true`
Whether to prefer built-in modules (e.g. `fs`, `path`) or local ones with the same names
### `jail`
Type: `String`
Default: `'/'`
Lock the module search in this path (like a chroot). Modules defined outside this path will be marked as external.
### `only`
Type: `Array[...String|RegExp]`
Default: `null`
Example: `only: ['some_module', /^@some_scope\/.*$/]`
### `modulesOnly`
Type: `Boolean`
Default: `false`
If true, inspect resolved files to check that they are ES2015 modules.
### `dedupe`
Type: `Array[...String]`
Default: `[]`
Force resolving for these modules to root's node_modules that helps to prevent bundling the same package multiple times if package is imported from dependencies.
```
dedupe: [ 'my-package', '@namespace/my-package' ]
```
This will deduplicate bare imports such as:
```js
import 'my-package';
import '@namespace/my-package';
```
And it will deduplicate deep imports such as:
```js
import 'my-package/foo.js';
import '@namespace/my-package/bar.js';
```
### `customResolveOptions`
Type: `Boolean`
Default: `null`
Any additional options that should be passed through to node-resolve.
```
customResolveOptions: {
moduleDirectory: 'js_modules'
}
```
### `rootDir`
Type: `String`
Default: `process.cwd()`
Root directory to resolve modules from. Used when resolving entrypoint imports, and when resolving deduplicated modules. Useful when executing rollup in a package of a monorepository.
```
// Set the root directory to be the parent folder
rootDir: path.join(process.cwd(), '..')
```
## Using with @rollup/plugin-commonjs
Since most packages in your node_modules folder are probably legacy CommonJS rather than JavaScript modules, you may need to use [@rollup/plugin-commonjs](https://github.com/rollup/plugins/packages/commonjs):
```js
// rollup.config.js
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';
export default {
input: 'main.js',
output: {
file: 'bundle.js',
format: 'iife',
name: 'MyModule'
},
plugins: [resolve(), commonjs()]
};
```
## Resolving Built-Ins (like `fs`)
This plugin won't resolve any builtins (e.g. `fs`). If you need to resolve builtins you can install local modules and set `preferBuiltins` to `false`, or install a plugin like [rollup-plugin-node-builtins](https://github.com/calvinmetcalf/rollup-plugin-node-builtins) which provides stubbed versions of these methods.
If you want to silence warnings about builtins, you can add the list of builtins to the `externals` option; like so:
```js
import resolve from '@rollup/plugin-node-resolve';
import builtins from 'builtin-modules'
export default ({
input: ...,
plugins: [resolve()],
external: builtins,
output: ...
})
```
## Meta
[CONTRIBUTING](/.github/CONTRIBUTING.md)
[LICENSE (MIT)](/LICENSE)