@pirxpilot/metalsmith-esbuild

Fork of @metalsmith/js-bundle without ES5 support.

A metalsmith plugin that bundles your JS using esbuild with sensible defaults.

Features

• Supports most ESbuild options including custom loaders and plugins

Installation

NPM:

npm install @pirxpilot/metalsmith-esbuild

Yarn:

yarn add @pirxpilot/metalsmith-esbuild

Usage

Pass @pirxpilot/metalsmith-esbuild to metalsmith.use :

const jsBundle = require('@pirxpilot/metalsmith-esbuild')

metalsmith.use(
  jsBundle({
    // defaults
    entries: {
      index: 'lib/index.js'
    }
  })
)

const isProd = metalsmith.env('NODE_ENV') !== 'development'
metalsmith.use(
  jsBundle({
    // explicit defaults
    bundle: true,
    minify: isProd,
    sourcemap: !isProd,
    platform: 'browser',
    target: 'es6',
    assetNames: '[dir]/[name]',
    // accessible as process.env.<NAME> in your JS files
    define: metalsmith.env(),
    // removes console & debugger statements
    drop: isProd ? ['console', 'debugger'] : [],
    entries: {
      index: 'lib/index.js'
    }
  })
)

The paths in the entries option should be relative to metalsmith.directory().

Options

@pirxpilot/metalsmith-esbuild provides access to most underlying esbuild options, with a few notable differences:

The options absWorkingDir (=metalsmith.directory()), outdir (=metalsmith.destination()), write (=false), and metafile (=true) can not be set, they are determined by the plugin.

The option entryPoints is renamed to entries. Specify entries as a {'target': 'path/to/source.js' }} object, and mind that the target should not have an extension.

The option define is automatically filled with with metalsmith.env(), but can be overwritten if desired. metalsmith.env('DEBUG') would be accessible in the bundle as process.env.DEBUG.

Loading assets

You can load assets with any of the ESbuild loaders by specifying a loader map. By default there is support for .js,.ts,.css,.json,.jsx,.tsx, and .txt loading. It's important to note 2 things:

• assets loaded with any loader but the file loader will be "embedded" in the resulting JS bundle and removed from the build (=not available for other plugins), increasing bundle size.
• if you would like to process assets loaded with the file loader with other metalsmith plugins (eg metalsmith-imagemin) @pirxpilot/metalsmith-esbuild needs to be run first and you should not overwrite the default assetNames option [dir]/[name].

The file loader is the loader you need for most large asset types you wouldn't want to bloat your JS bundle with. If you want to use inline SVG's, you would set its loader to text, while if you prefer loading them in image tags, you could set them to dataurl (embedded) or file (external).

The publicPath option will prepend a path to each asset loaded with the file loader. This can be useful if you are serving the metalsmith build from a non-root URI.

metalsmith.use(
  jsbundle({
    entries: { index: 'src/index.js' },
    loader: {
      '.png': 'file',
      '.svg': 'dataurl',
      '.jpg': 'file', // this will be a relative URI
      '.yaml': 'text' // this will be a parseable string
    },
    publicPath: metalsmith.env('NODE_ENV') === 'development' ? '' : 'https://johndoe.com'
  })
)

Debug

To enable debug logs, set metalsmith.env('DEBUG', '@pirxpilot/metalsmith-esbuild*') or in metalsmith.json: "env": { "DEBUG": "@pirxpilot/metalsmith-esbuild*" }. You can also pass the live environment variable by running metalsmith.env('DEBUG', process.env.DEBUG) or in metalsmith.json: "env": { "DEBUG": "$DEBUG" }

Alternatively you can set DEBUG to @metalsmith/* to debug all Metalsmith core plugins.

CLI usage

To use this plugin with the Metalsmith CLI, add @pirxpilot/metalsmith-esbuild to the plugins key in your metalsmith.json file:

{
  "plugins": [
    {
      "@pirxpilot/metalsmith-esbuild": {
        "entries": {
          "app": "lib/main.js"
        }
      }
    }
  ]
}

License

MIT