Webpack parts

Type and null safe, composable, webpack config for typescript.

Docs

Example

Basic shape

  const configFactory: ChainableConfigDefinition = 
    config =>
      reader.of({ ...config })

  const myDefaults = {}
  const myEnvironment: UserConfig = {
    target: 'node',
    dist: '...'
  }

  const myConfig = 
    configFactory(myDefaults)
      .run(myEnvironment)

Extending UserConfig with type interference

interface MyCustomConfig extends UserConfig {
  babelConfig: any
  ssr: boolean
}

const configFactory: ChainableConfigDefinition<MyCustomConfig> = config => 
  makeConfig<MyCustomConfig>(config)
    .chain(chainableDefaults)

const myConfig = 
  configFactory(myDefaults)
    .run(myEnvironment)

• or with module module augmentation feature - benefit is that, there is no need to pass extra parameter

declare module '@hungry/webpack-parts' {
  interface UserConfig {
    yourCustomConfigInterface: MyExtraConfig
  }
}

You can find babel example within loaders.

Asking for UserConfig when chaining

const setDevTool: ConfigPart<DevTool> = asks(userConfig =>
  isProduction(userConfig)
    ? 'source-map'
    : 'cheap-eval-source-map'
)

const configFactory = myConfig
  .ap(setDevTool.map(withDevTool.set)) // read (ask) and write (lens)

With webpack dev server

  configSomehow()
    .ap(attachDevServer.map(devServer.set))
    .run(myEnvironment)

Working with HMR

• there is a helper which adding all needed hmr scripts based upon env to run, addHMRScripts

  myConfig.chain(config =>
    asks(({ hmr, env }) => withEntry.set(({
      main: hmr && (env === 'development' || env === 'none')
        ? addHMRScripts(getFileInSRCFolder('index.browser.tsx'), config)
        : getFileInSRCFolder('index.browser.tsx'),
      static: getFileInSRCFolder('index.ssr.tsx'),
    }))(config))

• why? when running webpack-dev-server with hot it assumes that all entry points needs to be compiled with hmr and it is causing some issues during ssr rendering. I like this approach better since it is clear to which entry point extra code will be added.

More advance shape

You can find a more advance example within src/factory.ts file.

const chainableDefaults: ChainableConfigDefinition = config =>
  reader
    .of({ ...config })
    .map(umdOutput)
    .map(setExtensions)
    .map(setMainFields)
    .ap(setDevTool.map(withDevTool.set))
    .ap(setWebpackMode.map(withMode.set))
    .ap(sassRules.map(applyRuleAtTheEnd))
    .ap(codeRules.map(applyRuleAtTheEnd))
    .ap(outputEnv.map(partialOutput =>
      withOutput.modify(output => ({ ...output, ...partialOutput }))))
    .ap(pluginsBundle.map(applyPluginAtTheEnd))
    .chain(graphqlRule)

How to use it

It is used in conjunction with @hungry/webpack-parallel - dev friendly builder and watcher for webpack.

Working example

You can find basic working example within webpack-parallel/tests.

Motivation

In world of monorepos, there could be a tons of different configurations - at some point I had low level of trust on existing solutions, and production grade configs were hard to track and understand at first sight, so I needed something more bulletproof, easy to change - something which would sound correct without too much details. For me it was hard to create n-variation to any occasions and be fluent with that since code was growing and I was afraid that at some point I will loose momentum, so general idea behind this is - allow to provide any change, however within context where it will be used rather than having it prepare somewhere, far away from context. This makes config more flexible and provide abstraction over structure, so it should be pretty safe for the future and even providing any experimental configuration does not end up with total crash.

Implementation details

Whole configuration is based upon monad Reader and Lenses. Reader give you ability to compose any chunk of information and ability to run it within some part of common configuration. Lenses allow you to override any path in immutable type safe way. Previously I was using ramda but it was hard to keep it small and type safe - I was not satisfied by type interference. So if you are still using ramda in typescript world, please have a look on fp-ts and monocle-ts library, since for me it was a game changer. Cheers!