act/pkg/runner/testdata/actions/node16/node_modules/@vercel/ncc

ncc

Simple CLI for compiling a Node.js module into a single file, together with all its dependencies, gcc-style.

Motivation

• Publish minimal packages to npm
• Only ship relevant app code to serverless environments
• Don't waste time configuring bundlers
• Generally faster bootup time and less I/O overhead
• Compiled language-like experience (e.g.: go)

Design goals

• Zero configuration
• TypeScript built-in
• Only supports Node.js programs as input / output
• Support all Node.js patterns and npm modules

Usage

Installation

npm i -g @vercel/ncc

Usage

$ ncc <cmd> <opts>

Eg:

$ ncc build input.js -o dist

Outputs the Node.js compact build of input.js into dist/index.js.

Note: If the input file is using a .cjs extension, then so will the corresponding output file. This is useful for packages that want to use .js files as modules in native Node.js using a "type": "module" in the package.json file.

Commands:

  build <input-file> [opts]
  run <input-file> [opts]
  cache clean|dir|size
  help
  version

Options:

  -o, --out [file]         Output directory for build (defaults to dist)
  -m, --minify             Minify output
  -C, --no-cache           Skip build cache population
  -s, --source-map         Generate source map
  --no-source-map-register Skip source-map-register source map support
  -e, --external [mod]     Skip bundling 'mod'. Can be used many times
  -q, --quiet              Disable build summaries / non-error outputs
  -w, --watch              Start a watched build
  --v8-cache               Emit a build using the v8 compile cache
  --license [file]         Adds a file containing licensing information to the output
  --stats-out [file]       Emit webpack stats as json to the specified output file

Execution Testing

For testing and debugging, a file can be built into a temporary directory and executed with full source maps support with the command:

$ ncc run input.js

With TypeScript

The only requirement is to point ncc to .ts or .tsx files. A tsconfig.json file is necessary. Most likely you want to indicate es2015 support:

{
  "compilerOptions": {
    "target": "es2015",
    "moduleResolution": "node"
  }
}

Package Support

Some packages may need some extra options for ncc support in order to better work with the static analysis.

See package-support.md for some common packages and their usage with ncc.

Programmatically From Node.js

require('@vercel/ncc')('/path/to/input', {
  // provide a custom cache path or disable caching
  cache: "./custom/cache/path" | false,
  // externals to leave as requires of the build
  externals: ["externalpackage"],
  // directory outside of which never to emit assets
  filterAssetBase: process.cwd(), // default
  minify: false, // default
  sourceMap: false, // default
  sourceMapBasePrefix: '../', // default treats sources as output-relative
  // when outputting a sourcemap, automatically include
  // source-map-support in the output file (increases output by 32kB).
  sourceMapRegister: true, // default
  watch: false, // default
  license: '', // default does not generate a license file
  v8cache: false, // default
  quiet: false, // default
  debugLog: false // default
}).then(({ code, map, assets }) => {
  console.log(code);
  // Assets is an object of asset file names to { source, permissions, symlinks }
  // expected relative to the output code (if any)
})

When watch: true is set, the build object is not a promise, but has the following signature:

{
  // handler re-run on each build completion
  // watch errors are reported on "err"
  handler (({ err, code, map, assets }) => { ... })
  // handler re-run on each rebuild start
  rebuild (() => {})
  // close the watcher
  void close ();
}

Caveats

• Files / assets are relocated based on a static evaluator. Dynamic non-statically analyzable asset loads may not work out correctly