In this guide you will learn to create a configuration for your project.


All Paths are relative to the current working directory. Maven projects default to src/main/frontend.

Your configuration file must be in crafty.config.js

In its simplest form a configuration can look like this.

module.exports = {
  presets: [
  js: {
    app: {
      // Will create js/app.min.js containing both source files
      source: ["js/panel.js", "js/nothing.js"]

More advanced configuration can look like this:

module.exports = {
  presets: [
  name: "test-plugin",
  mavenType: "webjar", // This artifact is a webjar
  css: {
    testIndex: {
      source: "css/test.scss", // You can specify one or more entry files
      destination: "index.min.css", // You can make the destination explicit
      watch: "css/**/*.scss" // When a change occurs on files corresponding to this patterns this task will be rerun
    testIndex2: {
      source: ["css/test2.scss", "css/more.scss"],
      destination: "index2.min.css",
      watch: "css/**/*.scss"
  js: {
    app: {
      runner: "webpack", // Use Webpack and Babel to compile this bundle
      source: "js/app.js"


Each feature of Crafty is declared through a preset, if you wish to compile your JavaScript with Babel, we created crafty-preset-babel. If you wish to compile your CSS with PostCSS, we created crafty-preset-postcss.

All these presets can create Tasks which are then taken by a Runner. We provide three runners: crafty-runner-gulp, crafty-runner-webpack and crafty-runner-rollup.


A bundle is a set of one or more source files that will be compiled in a single destination file.

Each bundle has one mandatory option : source.

If we take this JavaScript bundle :

app: { // name of the bundle
    source: ['js/panel.js', 'js/nothing.js'],

This will automatically create a file in <destination_js>/app.min.js containing both source files that will be minified.

The file name is taken from the bundle name if no destination is specified

Common Bundle options

Option Type Optional ? Description
source String/Array No One single file or an array of files you wish to compile. Glob expressions are valid.
runner String No The name of the runner to use for this bundle. Is mandatory if more than one runner is loaded
destination String Yes The name to give to the final file. Defaults to <bundle_name>.min.<bundle_type>
watch String/Array Yes The watch expression to use to rebuild this asset. Any glob expression is valid, is needed for Gulp in watch mode.

Bundles have more options that are specific to the selected runners and bundle types.

CSS Bundles (crafty-preset-postcss)

testIndex: {
    source: 'css/test/test.scss',
    destination: 'index.min.css',
    watch: 'css/test/**.scss'

testIndex is the bundle name, you will be able to call crafty css_testIndex to build it.

The preset itself documents all options and features that are available to you.

More about crafty-preset-postcss

JavaScript Bundles (crafty-preset-babel or crafty-preset-typescript)

app: {
    source: ['js/panel.js', 'js/nothing.js'],
    destination: 'app.min.js'

app is the bundle name, you will be able to call crafty run js_app to build it.

Apart from the common options, here are the options you can use for JavaScript bundles. The presets document all options and features that are available to you.

More about crafty-preset-babel
More about crafty-preset-typescript

Images (crafty-preset-images or crafty-preset-images-simple)

You can add the crafty-preset-images or crafty-preset-images-simple package to your project to be able to compress your jpg, png, gif and svg files (images-simple will compress svg and copy the rest).

More about crafty-preset-images
More about crafty-preset-images-simple

Naming and locations conventions


Your assets can be located anywhere you want next to your package.json and crafty.config.js but we recommend putting them inside a sub-directory:

  • js for JavaScript / TypeScript files
  • css for Style sheets
  • images for images

If you have some external JavaScript or CSS that aren’t available in NPM. You can also use create a vendor directory either in the js/css folder or in frontend if your libraries contains both JavaScript and CSS files.

Bundle names

Your bundle names should have an expressive name, if you have a single bundle, name it either “app” or the name of your application.

Bundle destinations

When setting a destination, you should always prefix the extension with “.min” for example file.min.js or file.min.css

This is a convention that allows some tools to know the content is minified. And will bring you the following benefits :

  • When compressing files together, a file with “.min” in the name will not be minified again, thus you get a performance boost.
  • Files with “.min” in their names won’t go through the linting hooks.

Destination directory

By default, your compiled assets will be in dist/<bundleType>. But you can override the config.destination or config.destination_<bundleType> option.

You can also use the crafty-preset-maven with the mavenType option to move your assets to Maven’s target directory.

More about crafty-preset-maven

All Options

Crafty has options that can be tweaked, the exhaustive documentation is available here.