Project Configuration with wpackio.project.js

The wpackio.project.js file at the root of your workspace tells wpackio how your project is to be compiled. When you bootstrap this file is created for you.

You should commit wpackio.project.js with your VCS.

A typical project file looks like this.

module.exports = {
	// Project Identity
	appName: 'wpackplugin', // Unique name of your project
	type: 'plugin', // Plugin or theme
	slug: 'wpackio-plugin', // Plugin or Theme slug, basically the directory name under `wp-content/<themes|plugins>`
	// Used to generate banners on top of compiled stuff
	bannerConfig: {
		name: 'WordPress WebPack Bundler',
		author: 'Swashata Ghosh',
		license: 'GPL-3.0',
		link: '',
		version: '1.0.0',
			'This software is released under the GPL-3.0 License\n',
		credit: true,
	// Files we need to compile, and where to put
	files: [
		// If this has length === 1, then single compiler
			name: 'app',
			entry: {
				main: ['./src/app/index.js'],
				mobile: ['./src/app/mobile.js'],
			// Extra webpack config to be passed directly
			webpackConfig: undefined,
		// If has more length, then multi-compiler
			name: 'foo',
			entry: {
				main: ['./src/foo/foo.js'],
			// Extra webpack config to be passed directly
			webpackConfig: undefined,
		// Another app just for showing react
			name: 'reactapp',
			entry: {
				main: ['./src/reactapp/index.jsx'],
	// Output path relative to the context directory
	// We need relative path here, else, we can not map to publicPath
	outputPath: 'dist',
	// Project specific config
	// Needs react?
	hasReact: true,
	// Needs sass?
	hasSass: true,
	// Externals
	externals: {
		jquery: 'jQuery',
	// Webpack Aliases
	alias: undefined,
	// Show overlay on development
	errorOverlay: true,
	// Auto optimization by webpack
	// Split all common chunks with default config
	// <>
	// Won't hurt because we use PHP to automate loading
	optimizeSplitChunks: true,
	// Usually PHP and other files to watch and reload when changed
	watch: 'inc/**/*.php',
	// Use babel.config.js instead of built-in options
	useBabelConfig: false;
	// Hook into babeloverride so that we can add react-hot-loader plugin
	jsBabelOverride: defaults => ({
		plugins: ['react-hot-loader/babel'],
	// Files that you want to copy to your ultimate theme/plugin package
	// Supports glob matching from minimatch
	// @link <>
	packageFiles: [
	// Path to package directory, relative to the root
	packageDirPath: 'package',
	// Level of zlib compression, when creating archive
	zlibLevel: 4,

Let’s dive in deep with different options.

appName (string)

The name of your application. It should be unique and you have to use the same value with the PHP consumer library.

NOTE: This must be camelCase.

type (string)

Either plugin or theme, depending on your WordPress project.

slug (string)

The slug of your plugin or theme. This is the name of the directory put under wp-content/{themes,plugins}. This is used only for development purpose and has no significance on production build.

bannerConfig (Object)

A configuration object for banner put above all minified code.

It has the following properties:

  • name (string): Name of application.
  • author (string): Author of application.
  • version (string): Version of application.
  • link (string): Homepage link of application.
  • license (string): License of application.
  • copyrightText (string): Additional copyright text.
  • credit (boolean): Whether to give wpackio a little credit ❤️.

files (Array)

An array of file object. It defines which files to compile and supports code-splitting with different entry-points.

Unlike webpack entry-point it has to be an array of object of a certain shape. First let us see an example.

module.exports = {
	// ...
	// Files we need to compile, and where to put
	files: [
		// If this has length === 1, then single compiler
			name: 'app',
			entry: {
				main: ['./src/app/index.js'],
				mobile: ['./src/app/mobile.js'],
			// Extra webpack config to be passed directly
			webpackConfig: undefined,
	// ...

Here we have passed only one file object to the files entry. In most of the cases this is what we’d need. Our main entry will split codes depending on different entry-points and the tooling will handle chunk-splitting, optimization, prevent duplicates etc. More information is found here.

Once again, do note that you do not really need to do anything apart from defining = string[] logically. Just think about which single JS file you will need to run a particular application. Even if you have only one property under entry, then also (if needed) chunk-splitting will be applied.

If we were to pass multiple file object, then webpack would run in multi-compiler mode, separating dependency tree from each of the file object.

Each file object has two required and three optional properties. Here’s the interface.

interface EntryConfig {
	[x: string]: string[] | string;

interface FileConfig {
	name: string;
	entry: EntryConfig;
	typeWatchFiles?: string[];
	hasTypeScript?: boolean;
		| webpack.Configuration
		| ((
				config: webpack.Configuration,
				api: merge,
				appDir: string,
				isDev: boolean
		  ) => webpack.Configuration);

name (string) required:

A unique name of this file entry. If you are using more than one file entry, then make sure to give different names, otherwise the compiler might not work in development mode.

entry (object) required:

This is the path (relative to project root) of files you would like to compile.

const entry = {
	foo: ['./src/app/foo.js'],
	bar: './src/app/bar.js',

As you can see, we only support Object Syntax of webpack entry.

The reason is, we do our own little magic (covered in the concepts section) to define dynamic publicPath from WordPress API itself.

webpackConfig (Function | Object | undefined)

If you’d like to extend webpack configuration, then this is where you’d put your code.

It can support both webpack configuration objects or function to get further control. Kindly read the Extending Webpack Config under tutorials.

Callback Function

The most powerful form is the function. It has the following signature

type webpackConfigCallback = (
	config: webpack.Configuration,
	merge: webpackMerge,
	appDir: string,
	isDev: boolean
) => webpack.Configuration;
config (webpack.Configuration)

The configuration calculated by @wpackio/scripts is passed as the first parameter.

merge (webpackMerge)

The webpack-merge passed as-is.

appDir (string)

Directory inside outputPath where all the assets are to be emitted.

isDev (boolean)

Whether the operation is going for development mode or production build.

typeWatchFiles (string[])

Array of glob pattern for which typescript reports are to be notified.

hasTypeScript (boolean | undefined)

Explicitly disable typescript type assertions.

More information about typescript related options can be found here.

outputPath (string):

Name of the directory (relative) where we would put the bundled and manifest files. Defaults to dist and you should not commit this directory in your VCS.

NOTE: This must be a single directory name with alphanumeric camelCase. You can not pass rel/path/to/dist here.

hasReact (boolean):

Where you need support for react specific presets, like jsx.

hasSass (boolean):

Where you need support for sass/scss files. You need to install node-sass or dart-sass and your project’s devDependency yourself.

hasFlow (boolean):

Whether you need support for flowtype.

useBabelConfig (boolean)

wpackio-scripts knowingly avoids any babel.config.js and .babelrc file from babel-loader. If you wish to avoid this behavior and want to be in control of babel configuration, set this option to true.

More information about it can be read here.

jsBabelPresetOptions (object) | tsBabelPresetOptions (object)

wpackio script uses its own preset for javascript and typescript files. Using this option you can pass in additional config and it will be spread over the default one.

jsBabelPresetOptions is applied for js,jsx files and tsBabelPresetOptions is applied for ts.tsx files.

jsBabelOverride (Function) | tsBabelOverride (Function)

Pass in a callback function to completely override options for babel-loader

The signature is

	defaults: string | { [x: string]: any }
) =>
string | { [x: string]: any }

Where defaults is the config created by tooling. Here’s an example we used to incorporate react hot loader.

module.exports = {
	// ...
	// Hook into babeloverride so that we can add react-hot-loader plugin
	jsBabelOverride: defaults => ({
		plugins: ['react-hot-loader/babel'],
	// ...

jsBabelOverride is applied for js,jsx files and tsBabelOverride is applied for ts.tsx files.

externals (Object)

Configure webpack external runtime dependency.

alias (Object)

Configure webpack resolve.alias.

errorOverlay (boolean)

Whether to show overlay during development mode when some error has occurred.

optimizeSplitChunks (boolean)

Whether or not to apply built-in optimization presets. Turn it off if you would like to do things manually.

We have the default config from webpack optimization split-chunks plugin with only exception of setting chunks to 'all'. We can do it safely because our PHP consumer library handles the enqueue.

watch (string)

Glob pattern to watch additional files and reload browser on change. Useful for watching .php files.

module.exports = {
	// ...
	watch: './(inc|includes)/**/*.php',

packageFiles (string[])

Array of glob patterns to copy files to the packageDirPath directory. This is used to create the distributable zip file.

WordPress allows uploading .zip files to install both theme and plugins. This option provides you a way to create such .zip file with wpackio-scripts pack command.

packageDirPath (string)

Relative path of directory where we would put the package files. You should add it to your .gitignore file. A subdirectory with name same as slug will always be created inside it.

The generated package file will also have name like <slug>.zip.

zlibLevel (number)

The level of zlib compression to use when creating the zip.

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