setup-node/README.md

# setup-node

<p align="left">
  <a href="https://github.com/actions/setup-node/actions?query=workflow%3Abuild-test"><img alt="build-test status" src="https://github.com/actions/setup-node/workflows/build-test/badge.svg"></a> <a href="https://github.com/actions/setup-node/actions?query=workflow%3Aversions"><img alt="versions status" src="https://github.com/actions/setup-node/workflows/versions/badge.svg"></a> <a href="https://github.com/actions/setup-node/actions?query=workflow%3Aproxy"><img alt="proxy status" src="https://github.com/actions/setup-node/workflows/proxy/badge.svg"></a> 
</p>

This action provides the following functionality for GitHub Actions users:

- Optionally downloading and caching distribution of the requested Node.js version, and adding it to the PATH
- Optionally caching npm/yarn/pnpm dependencies
- Registering problem matchers for error output
- Configuring authentication for GPR or npm

# Usage

See [action.yml](action.yml)

**Basic:**
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-node@v2
  with:
    node-version: '14'
- run: npm install
- run: npm test
```

The `node-version` input is optional. If not supplied, the following files are checked:

1. `.n-node-version`
2. `.naverc`
3. `.node-version`
4. `.nodeenvrc`
5. `.nvmrc` (accurately [parsing nvm versions](https://github.com/ehmicky/node-version-alias))
6. `package.json#engines.node`

and finally the following environment variables:

7. `NODIST_NODE_VERSION`
8. `NODE_VERSION`
9. `DEFAULT_NODE_VERSION`

If none of these are present, finally the node version from PATH will be used. However, it is recommended to always specify Node.js version and don't rely on the system one.

> Behind the scenes, it uses [@ehmicky](https://github.com/ehmicky)'s [`preferred-node-version`](https://www.npmjs.com/package/) 😍.

The action will first check the local cache for a semver match. If unable to find a specific version in the cache, the action will attempt to download a version of Node.js. It will pull LTS versions from [node-versions releases](https://github.com/actions/node-versions/releases) and on miss or failure will fall back to the previous behavior of downloading directly from [node dist](https://nodejs.org/dist/).

For information regarding locally cached versions of Node.js on GitHub hosted runners, check out [GitHub Actions Virtual Environments](https://github.com/actions/virtual-environments).

#### Supported version syntax
The `node-version` input supports the following syntax:

major versions: `12`, `14`, `16`  
more specific versions: `10.15`, `14.2.0`, `16.3.0`  
nvm lts syntax: `lts/erbium`, `lts/fermium`, `lts/*`  

## Caching packages dependencies

The action has a built-in functionality for caching and restoring dependencies. It uses [actions/cache](https://github.com/actions/cache) under hood for caching dependencies but requires less configuration settings. Supported package managers are `npm`, `yarn`, `pnpm` (v6.10+). The `cache` input is optional, and caching is turned off by default.

The action defaults to search for the dependency file (`package-lock.json` or `yarn.lock`) in the repository root, and uses its hash as a part of the cache key. Use `cache-dependency-path` for cases when multiple dependency files are used, or they are located in different subdirectories.

See the examples of using cache for `yarn` / `pnpm` and  `cache-dependency-path` input in the [Advanced usage](docs/advanced-usage.md#caching-packages-dependencies) guide.

**Caching npm dependencies:**
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-node@v2
  with:
    node-version: '14'
    cache: 'npm'
- run: npm install
- run: npm test
```

**Caching npm dependencies in monorepos:**
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-node@v2
  with:
    node-version: '14'
    cache: 'npm'
    cache-dependency-path: subdir/package-lock.json
- run: npm install
- run: npm test
```

## Matrix Testing:
```yaml
jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node: [ '12', '14', '16' ]
    name: Node ${{ matrix.node }} sample
    steps:
      - uses: actions/checkout@v2
      - name: Setup node
        uses: actions/setup-node@v2
        with:
          node-version: ${{ matrix.node }}
      - run: npm install
      - run: npm test
```
## Advanced usage

1. [Check latest version](docs/advanced-usage.md#check-latest-version)
2. [Using different architectures](docs/advanced-usage.md#architecture)
3. [Caching packages dependencies](docs/advanced-usage.md#caching-packages-dependencies)
4. [Using multiple operating systems and architectures](docs/advanced-usage.md#multiple-operating-systems-and-architectures)
5. [Publishing to npmjs and GPR with npm](docs/advanced-usage.md#publish-to-npmjs-and-gpr-with-npm)
6. [Publishing to npmjs and GPR with yarn](docs/advanced-usage.md#publish-to-npmjs-and-gpr-with-yarn)
7. [Using private packages](docs/advanced-usage.md#use-private-packages)

# License

The scripts and documentation in this project are released under the [MIT License](LICENSE)

# Contributions

Contributions are welcome!  See [Contributor's Guide](docs/contributors.md)

## Code of Conduct

:wave: Be nice.  See [our code of conduct](CONDUCT)