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A webpack helper to find dependencies of your project that require transpilation with Babel (and @babel/preset-env) by comparing your minimum Node.js engine against theirs (engines in package.json), and/or by determining their minimum Node.js engine or published ES2015/ES6+ source (module/jsnext:main in package.json) to require features provided by plugins and polyfills from @babel/preset-env.

This mainly aims to solve errors during minification in production builds, since some ES2015+ features like arrow functions are unsupported by the native UglifyJS webpack plugin through at least 3.x. See issues below for examples of this error and affected modules. Update: Webpack now uses Terser rather than Uglify for minification - this example may no longer be valid.

This module generates regular expressions to be used in the exclude or include properties of your babel-loader rule in your configuration.

Use

import babelEnvDeps from 'webpack-babel-env-deps'

export default {
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: [
          babelEnvDeps.exclude() // returns /node_modules(?!(/|\\)(detect-indent|request|...)(/|\\))/
        ],
        use: {
          loader: 'babel-loader',
          // specify options here or in `.babelrc`
          options: {
            presets: [
              [
                'env',
                {
                  targets: {
                    browsers: ['> 1%, last 2 versions, Firefox ESR'],
                    uglify: true
                  }
                }
              ]
            ]
          }
        }
      }
    ]
  }
}

Options

Functions exclude amd include accept an optional options object with following properties:

mainFields

?array | ?boolean

Optional. This should match your resolve.mainFields if you specify it in your webpack config, else it assumes the default of ['browser', 'module', 'main']. This is used to determine modules published with ES2015+ module support as module/jsnext:main, which by default webpack will load in preference to main, so that its engines field might reflect main support rather than module/jsnext:main support, so we must assume we must transpile the module/jsnext:main version.

If you want to disable module/jsnext:main detection, and rely only on engines, you can set mainFields to false explicitly. This would assume all dependencies with a module/jsnext:main field point to a graph of files that are fully transpiled down to code that can run in environments indicated by engines, other than retaining ES modules syntax (for tree-shaking or other purposes). This was the goal of the module field according to Rollup, but the jsnext:main field could have ambiguities (see this write-up), and package authors in the wild may not always respect these conventions, so caveat emptor!

except

?array | ?string | ?function

Optional. This adds exceptions to the inclusion or exclusion rules. For example, include({ except: ['foo'] }) will prevent foo from being included for transpilation even if it would normally meet the criteria. And exclude({ except: ['foo'] }) will include foo for transpilation even if it doesn't otherwise meet transpilation criteria.

engines

?object | ?boolean

Optional. This optionally overrides the engines key in your package.json. Or set to false to suppress any use of your engines for determining dependencies to transpile.

defaultEngines

?object | ?boolean

Optional. Default is false. This optionally provides the engines key when missing from any dependencies. For example, exclude({ defaultEngines: { 'node': '>= 4' } }) will assume that dependencies without engines require node 4, and determine transpilation normally. Or set to true to enable transpilation for dependencies without enough information. For example, exclude({ defaultEngines: true }).

Issues

Reference