Build System

WebFun uses the package manager yarn to manage dependencies and run build scripts.

The following tasks are defined in package.json and can be started using yarn <task-name> on the command line.

start -- Start a local web server for development.

By default this starts the server on localhost port 8080. You can change the hostname to listen on with the environment variable host. Some features like the service worker might require an HTTPS connection to work properly. If you place a self-signed certificate under config/ssl.key and config/ssl.pem the server will accept HTTPS connections.

Assuming you have mapped webfun.local to in your hosts file (like echo " webfun.local" >> /etc/hosts), you can use mkcert to generate certificates that will be valid on your system like this:

# change to the project directory
$ cd webfun
# create a certificate
$ mkcert -cert-file config/ssl.pem -key-file config/ssl.key webfun.local localhost ::1

# start the development server with the proper hostname
$ host=webfun.local yarn start

format -- Format source code files using eslint & prettier. You should always run this task before committing a code change to make sure everything is properly formatted and adheres es to the coding standards.

test -- Run basic test suite once without collecting code coverage.

test:cont -- Run unit test whenever a change is detected. This task does not collect collect code coverage for performance reasons.

test:full -- Run all tests and collect code coverage.

test:unit -- Run unit tests with code coverage enabled.

test:unit:cont -- Run unit tests with code coverage whenever a change is detected

build -- Clear build directory and run a fresh build suitable for production.

build:docs -- Build this documentation. This script requires mdbook to be installed, see documentation for details.


Webpack is used to bundle scripts and prepare other assets like css stylesheets, fonts and copy static files in production builds. The following configuration files are used for various tasks, all of them are located in the config directory:

webpack.commmon.js -- A shared configuration that is used as a base for the dev and test configurations. -- Configuration for the development task, the development web server with hot module reloading is defined here.

webpack.test.js -- Used for running tests -- Defines the production build

webpack.service-worker.js -- Defines the production build for the service worker script. This is in a separate file because splitting the service worker code via chunks does not produce a file that runs in the service worker context.

Custom Plugins

WebFun uses a few custom webpack plugins. These are all single-file scripts found in the config directory.

file-list-webpack-plugin -- Creates a list of files produce during a production build and stores it in a json file. This file is used to pre-load assets when the service worker is installed.

spy-on-imports-webpack-plugin -- This plugin rewrites imports created by Webpack so jasmine.spy can be used on wildcard module imports to mock dependencies during test execution:

import * as UtilModule from "src/util";

describe("some test", () => {
	beforeEach(() => spyOn(UtilModule, "download"));

	it("starts a download", () => {