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 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 node version from PATH will be used. However, It is recommended to always specify Node.js version and don't rely on system one.  

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 npm/yarn dependencies. Supported package managers are `npm`, `yarn`. The `cache` input is optional, and caching is turned off by default.

**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 yarn dependencies:**
```yaml
steps:
- uses: actions/checkout@v2
- uses: actions/setup-node@v2
  with:
    node-version: '14'
    cache: 'yarn'
- run: yarn install
- run: yarn test
```
Yarn caching handles both yarn versions: 1 or 2. 

> At the moment, only `lock` files in the project root are supported.

### 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. [Using multiple operating systems and architectures](docs/advanced-usage.md#multiple-operating-systems-and-architectures)
4. [Publishing to npmjs and GPR with npm](docs/advanced-usage.md#publish-to-npmjs-and-gpr-with-npm)
5. [Publishing to npmjs and GPR with yarn](docs/advanced-usage.md#publish-to-npmjs-and-gpr-with-yarn)
6. [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)