Webpack Configuration

Overview

App Builder bundles Runtime action code using Webpack. Users can specify Webpack configurations for individual actions, sets of actions, or entire projects. See the Webpack site for configuration options.

Configuration file

When Runtime action code is bundled during aio app build|run|deploy the action directory is searched for a webpack config file named *webpack-config.js. The search is done first in the directory of the action being built, then the parent directory, up to the project root.

• To specify a Webpack configuration for a single action, place the *webpack-config.js file in the action folder.

• To specify a Webpack configuration for a set of actions, place the *webpack-config.js file in the parent directory of your action folders.

• To specify a Webpack configuration for an entire project, place the *webpack-config.js file in the root directory of your project.

ES module syntax

App Builder does not currently support ES Module syntax. This file must be written in CommonJS, or failures will occur at build time.

Configuration types

App Builder supports exporting the following configuration types in *webpack-config.js:

Objects

module.exports = { 
  mode: 'development' 
}

Functions that return objects

module.exports = (env) => ({
  mode: 'development'
})

Functions that return arrays of objects

module.exports = (env) => ([
  {
    mode: 'development' 
  },
  {
    mode: 'production'
  }
])

Asynchronous functions that return objects

module.exports = async (env) => ({
  mode: 'development'
})

Asynchronous functions that return arrays of objects

module.exports = async (env) => ([
  {
    mode: 'development' 
  },
  {
    mode: 'production'
  }
])

Arrays of objects

module.exports = [
  {
    mode: 'development'
  },
  {
    mode: 'production'
  }
]

Arrays of functions that return objects

module.exports = [
  (env) => ({
    mode: 'development'
  }),
  (env) => ({
    mode: 'production'
  })
]

Arrays of asynchronous functions that return objects

module.exports = [
  async (env) => ({
    mode: 'development'
  }),
  async (env) => ({
    mode: 'production'
  })
]

Configuration

Overview

Assuming that config contains your Webpack configuration:

{
  mode: config.mode || 'production', 
  optimization: {
    minimize: config.optimization.minimize || false
  },
  output: { 
    libraryTarget: config.output.libraryTarget || 'commonjs2',
    path: './dist/${actionPath}/${actionName}-temp/' // Cannot change 
    fileName: `${output.path}/index.js` // Cannot change 
  },
  target: 'node' // Cannot change
  entry: [
    '<path to the action>', 
    ...config.entry
  ],
  resolve: { 
    extensions: [
      '.js', 
      '.json', 
      ...config.extensions
    ],
    mainFields: [ 
      'main',
      ...config.mainFields
    ]
  },
  plugins: [
    new DefaultPlugin({
      WEBPACK_ACTION_BUILD: 'true', 
      `process.env.AIO_CLI_ENV`: ${cliEnv}
    }),
    ...config.plugins
  ]

  // ... All other Webpack configuration options are valid

}

Base options

App Builder starts off with these Webpack configuration options; any additional values will be added on for these fields:

• entry always contains the path to the action; additional paths identified in your configuration file will be added on
• resolve.extensions always contains .js and .json; additional extensions identified in your configuration file will be added on.
• resolve.mainFields always contains main; additional main fields identified in your configuration file will be added on.

Defaults

App Builder defaults to the following Webpack configuration options if they are not present in your configuration file:

• output.libraryTarget defaults to commonjs2
• mode defaults to production
• optimization.minimize defaults to false

Immutable options

App Builder does not allow changing of these Webpack configuration options; if these fields are present in your configuration file, they will be ignored:

• target must be node; I/O Runtime supports only Node.js as a runtime
• output.pathmust be ./dist/${actionPath}/${actionName}-temp/
• output.filename must be ${output.path}/index.js
  • Note: If you are supplying multiple configurations, this will be true for the first configuration; subsequent configurations will be ${output.path}/index.[hashname].js

Environment variables

If you export a function, an asynchronous function, or an array of functions from your Webpack configuration file, App Builder will pass the environment to those functions. You can use this to make decisions about bundling based on the environment.

For example, if you export an environment variable called FEATURE_FLAG_PIRATES_BOUNTY before building your application, you can use it in your Webpack configuration file:

module.exports = (env) => ({
  mode: env.FEATURE_FLAG_PIRATES_BOUNTY ? 'production' : 'development'
})

Next steps

Return to Configuration.

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