webpack-chain.md

webpack-chain: Neutrino configuration API

Use a chaining API to generate and simplify the modification of webpack 2 and 3 configurations.

This documentation corresponds to v4 of webpack-chain, which Neutrino utilizes.

Note: while webpack-chain is utilized extensively in Neutrino, the package is completely standalone and can be used by any project. See the webpack-chain repo for standalone documentation.

Introduction

webpack's core configuration is based on creating and modifying a potentially unwieldy JavaScript object. While this is OK for configurations on individual projects, trying to share these objects across projects and make subsequent modifications gets messy, as you need to have a deep understanding of the underlying object structure to make those changes.

webpack-chain attempts to improve this process by providing a chainable or fluent API for creating and modifying webpack configurations. Key portions of the API can be referenced by user-specified names, which helps to standardize how to modify a configuration across projects.

This is easier explained through the examples following.

Getting Started

In the Neutrino API, the config property is an instance of webpack-chain. For this guide, our example base configuration will be .neutrinorc.js in the root of our project directory. This can utilize either the Object format or Function format to access the Neutrino API:

// .neutrinorc.js

// Object format
module.exports = {
  use: [
    (neutrino) => {
      // access the Neutrino API
    }
  ]
};

// Function format
module.exports = (neutrino) => {
  // access the Neutrino API
};

In our examples we will utilize the Function format for sake of space.

// Make configuration changes using the chaining API.
// Every API call tracks a change to the stored configuration.
module.exports = (neutrino) => {
  neutrino.config
    // Interact with entry points
    .entry('index')
      .add('src/index.js')
      .end()

    // Modify output settings
    .output
      .path('dist')
      .filename('[name].bundle.js');

  // Create named rules which can be modified later or
  // in other middleware/presets
  neutrino.config.module
    .rule('lint')
      .test(/\.js$/)
      .pre()
      .include
        .add('src')
        .end()
      // Even create named uses (loaders)
      .use('eslint')
        .loader('eslint-loader')
        .options({
          rules: {
            semi: 'off'
          }
        });

  neutrino.config.module
    .rule('compile')
      .test(/\.js$/)
      .include
        .add('src')
        .add('test')
        .end()
      .use('babel')
        .loader('babel-loader')
        .options({
          presets: [
            ['babel-preset-es2015', { modules: false }]
          ]
        });

  // Create named plugins too!
  neutrino.config
    .plugin('clean')
      .use(CleanPlugin, [['dist'], { root: '/dir' }]);
};

ChainedMap

One of the core API interfaces in Neutrino configuration is a ChainedMap. A ChainedMap operates similar to a JavaScript Map, with some conveniences for chaining and generating configuration. If a property is marked as being a ChainedMap, it will have an API and methods as described below:

Unless stated otherwise, these methods will return the ChainedMap, allowing you to chain these methods.

// Remove all entries from a Map.
clear()

// Remove a single entry from a Map given its key.
// key: *
delete(key)

// Fetch the value from a Map located at the corresponding key.
// key: *
// returns: value
get(key)

// Set a value on the Map stored at the `key` location.
// key: *
// value: *
set(key, value)

// Returns `true` or `false` based on whether a Map as has a value set at a particular key.
// key: *
// returns: Boolean
has(key)

// Returns an array of all the values stored in the Map.
// returns: Array
values()

// Returns an object of all the entries in the backing Map
// where the key is the object property, and the value
// corresponding to the key. Will return `undefined` if the backing
// Map is empty.
// This will order properties by their name if the value is
// a ChainedMap that used .before() or .after().
// returns: Object, undefined if empty
entries()

// Provide an object which maps its properties and values
// into the backing Map as keys and values.
// You can also provide an array as the second argument
// for property names to omit from being merged.
// obj: Object
// omit: Optional Array
merge(obj, omit)

// Execute a function against the current configuration context
// handler: Function -> ChainedMap
  // A function which is given a single argument of the ChainedMap instance
batch(handler)

// Conditionally execute a function to continue configuration
// condition: Boolean
// whenTruthy: Function -> ChainedMap
  // invoked when condition is truthy, given a single argument of the ChainedMap instance
// whenFalsy: Optional Function -> ChainedMap
  // invoked when condition is falsy, given a single argument of the ChainedMap instance
when(condition, whenTruthy, whenFalsy)

ChainedSet

Another of the core API interfaces in Neutrino configuration is a ChainedSet. A ChainedSet operates similar to a JavaScript Set, with some conveniences for chaining and generating configuration. If a property is marked as being a ChainedSet, it will have an API and methods as described below:

Unless stated otherwise, these methods will return the ChainedSet, allowing you to chain these methods.

// Add/append a value to the end of a Set.
// value: *
add(value)

// Add a value to the beginning of a Set.
// value: *
prepend(value)

// Remove all values from a Set.
clear()

// Remove a specific value from a Set.
// value: *
delete(value)

// Returns `true` or `false` based on whether or not the
// backing Set contains the specified value.
// value: *
// returns: Boolean
has(value)

// Returns an array of values contained in the backing Set.
// returns: Array
values()

// Concatenates the given array to the end of the backing Set.
// arr: Array
merge(arr)

// Execute a function against the current configuration context
// handler: Function -> ChainedSet
  // A function which is given a single argument of the ChainedSet instance
batch(handler)

// Conditionally execute a function to continue configuration
// condition: Boolean
// whenTruthy: Function -> ChainedSet
  // invoked when condition is truthy, given a single argument of the ChainedSet instance
// whenFalsy: Optional Function -> ChainedSet
  // invoked when condition is falsy, given a single argument of the ChainedSet instance
when(condition, whenTruthy, whenFalsy)

Shorthand methods

A number of shorthand methods exist for setting a value on a ChainedMap with the same key as the shorthand method name. For example, devServer.hot is a shorthand method, so it can be used as:

// A shorthand method for setting a value on a ChainedMap
neutrino.config.devServer.hot(true);

// This would be equivalent to:
neutrino.config.devServer.set('hot', true);

A shorthand method is chainable, so calling it will return the original instance, allowing you to continue to chain.

Config

Moving to deeper points in the configuration API will change the context of what you are modifying. You can move back to the higher context by either referencing the top-level neutrino.config again, or by calling .end() to move up one level. If you are familiar with jQuery, .end() works similarly. All API calls will return the API instance at the current context unless otherwise specified. This is so you may chain API calls continuously if desired.

For details on the specific values that are valid for all shorthand and low-level methods, please refer to their corresponding name in the webpack docs hierarchy.

Config : ChainedMap

Config shorthand methods

neutrino.config
  .amd(amd)
  .bail(bail)
  .cache(cache)
  .devtool(devtool)
  .context(context)
  .externals(externals)
  .loader(loader)
  .parallelism(parallelism)
  .profile(profile)
  .recordsPath(recordsPath)
  .recordsInputPath(recordsInputPath)
  .recordsOutputPath(recordsOutputPath)
  .stats(stats)
  .target(target)
  .watch(watch)
  .watchOptions(watchOptions)

Config entryPoints

// Backed at config.entryPoints : ChainedMap
neutrino.config.entry(name) : ChainedSet

neutrino.config
  .entry(name)
    .add(value)
    .add(value)

neutrino.config
  .entry(name)
    .clear()

// Using low-level config.entryPoints:

neutrino.config.entryPoints
  .get(name)
    .add(value)
    .add(value)

neutrino.config.entryPoints
  .get(name)
    .clear()

Config output: shorthand methods

neutrino.config.output : ChainedMap

neutrino.config.output
  .auxiliaryComment(auxiliaryComment)
  .chunkFilename(chunkFilename)
  .chunkLoadTimeout(chunkLoadTimeout)
  .crossOriginLoading(crossOriginLoading)
  .devtoolFallbackModuleFilenameTemplate(devtoolFallbackModuleFilenameTemplate)
  .devtoolLineToLine(devtoolLineToLine)
  .devtoolModuleFilenameTemplate(devtoolModuleFilenameTemplate)
  .filename(filename)
  .hashFunction(hashFunction)
  .hashDigest(hashDigest)
  .hashDigestLength(hashDigestLength)
  .hashSalt(hashSalt)
  .hotUpdateChunkFilename(hotUpdateChunkFilename)
  .hotUpdateFunction(hotUpdateFunction)
  .hotUpdateMainFilename(hotUpdateMainFilename)
  .jsonpFunction(jsonpFunction)
  .library(library)
  .libraryExport(libraryExport)
  .libraryTarget(libraryTarget)
  .path(path)
  .pathinfo(pathinfo)
  .publicPath(publicPath)
  .sourceMapFilename(sourceMapFilename)
  .sourcePrefix(sourcePrefix)
  .strictModuleExceptionHandling(strictModuleExceptionHandling)
  .umdNamedDefine(umdNamedDefine)

Config resolve: shorthand methods

neutrino.config.resolve : ChainedMap

neutrino.config.resolve
  .cachePredicate(cachePredicate)
  .cacheWithContext(cacheWithContext)
  .enforceExtension(enforceExtension)
  .enforceModuleExtension(enforceModuleExtension)
  .unsafeCache(unsafeCache)
  .symlinks(symlinks)

Config resolve alias

neutrino.config.resolve.alias : ChainedMap

neutrino.config.resolve.alias
  .set(key, value)
  .set(key, value)
  .delete(key)
  .clear()

Config resolve modules

neutrino.config.resolve.modules : ChainedSet

neutrino.config.resolve.modules
  .add(value)
  .prepend(value)
  .clear()

Config resolve aliasFields

neutrino.config.resolve.aliasFields : ChainedSet

neutrino.config.resolve.aliasFields
  .add(value)
  .prepend(value)
  .clear()

Config resolve descriptionFields

neutrino.config.resolve.descriptionFields : ChainedSet

neutrino.config.resolve.descriptionFields
  .add(value)
  .prepend(value)
  .clear()

Config resolve extensions

neutrino.config.resolve.extensions : ChainedSet

neutrino.config.resolve.extensions
  .add(value)
  .prepend(value)
  .clear()

Config resolve mainFields

neutrino.config.resolve.mainFields : ChainedSet

neutrino.config.resolve.mainFields
  .add(value)
  .prepend(value)
  .clear()

Config resolve mainFiles

neutrino.config.resolve.mainFiles : ChainedSet

neutrino.config.resolve.mainFiles
  .add(value)
  .prepend(value)
  .clear()

Config resolveLoader

neutrino.config.resolveLoader : ChainedMap

Config resolveLoader extensions

neutrino.config.resolveLoader.extensions : ChainedSet

neutrino.config.resolveLoader.extensions
  .add(value)
  .prepend(value)
  .clear()

Config resolveLoader modules

neutrino.config.resolveLoader.modules : ChainedSet

neutrino.config.resolveLoader.modules
  .add(value)
  .prepend(value)
  .clear()

Config resolveLoader moduleExtensions

neutrino.config.resolveLoader.moduleExtensions : ChainedSet

neutrino.config.resolveLoader.moduleExtensions
  .add(value)
  .prepend(value)
  .clear()

Config resolveLoader packageMains

neutrino.config.resolveLoader.packageMains : ChainedSet

neutrino.config.resolveLoader.packageMains
  .add(value)
  .prepend(value)
  .clear()

Config performance: shorthand methods

neutrino.config.performance : ChainedMap

neutrino.config.performance
  .hints(hints)
  .maxEntrypointSize(maxEntrypointSize)
  .maxAssetSize(maxAssetSize)
  .assetFilter(assetFilter)

Config plugins

// Backed at config.plugins
neutrino.config.plugin(name) : ChainedMap

Config plugins: adding

NOTE: Do not use new to create the plugin, as this will be done for you.

neutrino.config
  .plugin(name)
    .use(WebpackPlugin, args)

// Examples
neutrino.config
  .plugin('hot')
    .use(webpack.HotModuleReplacementPlugin);

neutrino.config
  .plugin('env')
    .use(webpack.EnvironmentPlugin, ['NODE_ENV']);

Config plugins: modify arguments

neutrino.config
  .plugin(name)
    .tap(args => newArgs)

// Example
neutrino.config
  .plugin('env')
    .tap(args => [...args, 'SECRET_KEY']);

Config plugins: modify instantiation

neutrino.config
  .plugin(name)
    .init((Plugin, args) => new Plugin(...args));

Config plugins: removing

neutrino.config.plugins.delete(name)

Config plugins: ordering before

Specify that the current plugin context should operate before another named plugin. You cannot use both .before() and .after() on the same plugin.

neutrino.config
  .plugin(name)
    .before(otherName)
    
// Example

neutrino.config
  .plugin('html-template')
    .use(HtmlWebpackTemplate)
    .end()
  .plugin('script-ext')
    .use(ScriptExtWebpackPlugin)
    .before('html-template');

Config plugins: ordering after

Specify that the current plugin context should operate after another named plugin. You cannot use both .before() and .after() on the same plugin.

neutrino.config
  .plugin(name)
    .after(otherName)

// Example

neutrino.config
  .plugin('html-template')
    .after('script-ext')
    .use(HtmlWebpackTemplate)
    .end()
  .plugin('script-ext')
    .use(ScriptExtWebpackPlugin);

Config resolve plugins

// Backed at config.resolve.plugins
neutrino.config.resolve.plugin(name) : ChainedMap

Config resolve plugins: adding

NOTE: Do not use new to create the plugin, as this will be done for you.

neutrino.config.resolve
  .plugin(name)
    .use(WebpackPlugin, args)

Config resolve plugins: modify arguments

neutrino.config.resolve
  .plugin(name)
    .tap(args => newArgs)

Config resolve plugins: modify instantiation

neutrino.config.resolve
  .plugin(name)
    .init((Plugin, args) => new Plugin(...args))

Config resolve plugins: removing

neutrino.config.resolve.plugins.delete(name)

Config resolve plugins: ordering before

Specify that the current plugin context should operate before another named plugin. You cannot use both .before() and .after() on the same resolve plugin.

neutrino.config.resolve
  .plugin(name)
    .before(otherName)

// Example

neutrino.config.resolve
  .plugin('beta')
    .use(BetaWebpackPlugin)
    .end()
  .plugin('alpha')
    .use(AlphaWebpackPlugin)
    .before('beta');

Config resolve plugins: ordering after

Specify that the current plugin context should operate after another named plugin. You cannot use both .before() and .after() on the same resolve plugin.

neutrino.config.resolve
  .plugin(name)
    .after(otherName)

// Example

neutrino.config.resolve
  .plugin('beta')
    .after('alpha')
    .use(BetaWebpackTemplate)
    .end()
  .plugin('alpha')
    .use(AlphaWebpackPlugin);

Config node

neutrino.config.node : ChainedMap

neutrino.config.node
  .set('__dirname', 'mock')
  .set('__filename', 'mock');

Config devServer

neutrino.config.devServer : ChainedMap

Config devServer allowedHosts

neutrino.config.devServer.allowedHosts : ChainedSet

neutrino.config.devServer.allowedHosts
  .add(value)
  .prepend(value)
  .clear()

Config devServer: shorthand methods

neutrino.config.devServer
  .bonjour(bonjour)
  .clientLogLevel(clientLogLevel)
  .color(color)
  .compress(compress)
  .contentBase(contentBase)
  .disableHostCheck(disableHostCheck)
  .filename(filename)
  .headers(headers)
  .historyApiFallback(historyApiFallback)
  .host(host)
  .hot(hot)
  .hotOnly(hotOnly)
  .https(https)
  .inline(inline)
  .info(info)
  .lazy(lazy)
  .noInfo(noInfo)
  .open(open)
  .openPage(openPage)
  .overlay(overlay)
  .pfx(pfx)
  .pfxPassphrase(pfsPassphrase)
  .port(port)
  .progress(progress)
  .proxy(proxy)
  .public(public)
  .publicPath(publicPath)
  .quiet(quiet)
  .setup(setup)
  .socket(socket)
  .staticOptions(staticOptions)
  .stats(stats)
  .stdin(stdin)
  .useLocalIp(useLocalIp)
  .watchContentBase(watchContentBase)
  .watchOptions(watchOptions)

Config module

neutrino.config.module : ChainedMap

Config module: shorthand methods

neutrino.config.module : ChainedMap

neutrino.config.module
  .noParse(noParse)

Config module rules: shorthand methods

neutrino.config.module.rules : ChainedMap

neutrino.config.module
  .rule(name)
    .test(test)
    .pre()
    .post()
    .enforce(preOrPost)

Config module rules uses (loaders): creating

neutrino.config.module.rules{}.uses : ChainedMap

neutrino.config.module
  .rule(name)
    .use(name)
      .loader(loader)
      .options(options)

// Example

neutrino.config.module
  .rule('compile')
    .use('babel')
      .loader('babel-loader')
      .options({ presets: ['babel-preset-es2015'] });

Config module rules uses (loaders): modifying options

neutrino.config.module
  .rule(name)
    .use(name)
      .tap(options => newOptions)

// Example

neutrino.config.module
  .rule('compile')
    .use('babel')
      .tap(options => merge(options, { plugins: ['babel-plugin-syntax-object-rest-spread'] }));

Config module rules oneOfs (conditional rules):

neutrino.config.module.rules{}.oneOfs : ChainedMap<Rule>

neutrino.config.module
  .rule(name)
    .oneOf(name)

// Example

neutrino.config.module
  .rule('css')
    .oneOf('inline')
      .resourceQuery(/inline/)
      .use('url')
        .loader('url-loader')
        .end()
      .end()
    .oneOf('external')
      .resourceQuery(/external/)
      .use('file')
        .loader('file-loader')

---

Merging Config

Neutrino config supports merging in an object to the configuration instance which matches a layout similar to how the configuration schema is laid out. Note that this is not a webpack configuration object, but you may transform a webpack configuration object before providing it to Neutrino configuration to match its layout.

neutrino.config.merge({ devtool: 'source-map' });

neutrino.config.get('devtool') // "source-map"

// Neutrino configuration "schematic"
// Merging an object into Neutrino configuration
// should have any properties you set follow this
// "schematic" format.
neutrino.config.merge({
  [key]: value,

  amd,
  bail,
  cache,
  devtool,
  context,
  externals,
  loader,
  profile,
  recordsPath,
  recordsInputPath,
  recordsOutputPath,
  stats,
  target,
  watch,
  watchOptions,

  entry: {
    [name]: [...values]
  },

  plugin: {
    [name]: {
      plugin: WebpackPlugin,
      args: [...args],
      before,
      after
    }
  },

  devServer: {
    [key]: value,

    clientLogLevel,
    compress,
    contentBase,
    filename,
    headers,
    historyApiFallback,
    host,
    hot,
    hotOnly,
    https,
    inline,
    lazy,
    noInfo,
    overlay,
    port,
    proxy,
    quiet,
    setup,
    stats,
    watchContentBase
  },

  node: {
    [key]: value
  },

  performance: {
    [key]: value,

    hints,
    maxEntrypointSize,
    maxAssetSize,
    assetFilter
  },

  resolve: {
    [key]: value,

    alias: {
      [key]: value
    },
    aliasFields: [...values],
    descriptionFields: [...values],
    extensions: [...values],
    mainFields: [...values],
    mainFiles: [...values],
    modules: [...values],

    plugin: {
      [name]: {
        plugin: WebpackPlugin,
        args: [...args],
        before,
        after
      }
    }
  },

  resolveLoader: {
    [key]: value,

    extensions: [...values],
    modules: [...values],
    moduleExtensions: [...values],
    packageMains: [...values]
  },

  module: {
    [key]: value,

    rule: {
      [name]: {
        [key]: value,

        enforce,
        issuer,
        parser,
        resource,
        resourceQuery,
        test,

        include: [...paths],
        exclude: [...paths],

        oneOf: {
          [name]: Rule
        },

        use: {
          [name]: {
            loader: LoaderString,
            options: LoaderOptions,
            before,
            after
          }
        }
      }
    }
  }
})

Conditional configuration

When working with instances of ChainedMap and ChainedSet, you can perform conditional configuration using when. You must specify an expression to when() which will be evaluated for truthiness or falsiness. If the expression is truthy, the first function argument will be invoked with an instance of the current chained instance. You can optionally provide a second function to be invoked when the condition is falsy, which is also given the current chained instance.

// Example: Only add minify plugin during production
neutrino.config
  .when(process.env.NODE_ENV === 'production', config => {
    config
      .plugin('minify')
      .use(BabelMinifyWebpackPlugin);
  });

// Example: Only add minify plugin during production,
// otherwise set devtool to source-map
neutrino.config
  .when(process.env.NODE_ENV === 'production',
    config => config.plugin('minify').use(BabelMinifyWebpackPlugin),
    config => config.devtool('source-map')
  );