karma-chrome-launcher

What is karma-chrome-launcher?

The karma-chrome-launcher npm package is a plugin for Karma, a test runner for JavaScript. It allows developers to execute tests in the Chrome browser. It can launch Chrome in various modes, control browser instances, and integrate with continuous integration systems.

What are karma-chrome-launcher's main functionalities?

Launching Chrome for testing

This feature allows you to configure Karma to use Chrome as the browser for running tests. You simply add 'Chrome' to the 'browsers' array in your Karma configuration.

module.exports = function(config) {
  config.set({
    browsers: ['Chrome'],
    // ... other Karma configuration ...
  });
};

Running tests in headless Chrome

This feature enables you to run tests in a headless Chrome instance, which is useful for continuous integration environments where you don't need a visible UI.

module.exports = function(config) {
  config.set({
    browsers: ['ChromeHeadless'],
    // ... other Karma configuration ...
  });
};

Customizing Chrome flags

This feature allows you to customize the Chrome instance by adding command-line flags to alter its behavior for testing purposes.

module.exports = function(config) {
  config.set({
    customLaunchers: {
      Chrome_with_flags: {
        base: 'Chrome',
        flags: ['--disable-web-security', '--disable-gpu']
      }
    },
    browsers: ['Chrome_with_flags'],
    // ... other Karma configuration ...
  });
};

Other packages similar to karma-chrome-launcher

karma-firefox-launcher

This package is similar to karma-chrome-launcher but is used to launch Mozilla Firefox for running tests with Karma. It provides similar functionality for a different browser.

karma-safari-launcher

Similar to karma-chrome-launcher, this package allows you to run tests in the Safari browser. It is specifically tailored for Safari and provides comparable features for Karma integration.

karma-ie-launcher

This package is designed to launch Internet Explorer for testing with Karma. It offers similar capabilities to karma-chrome-launcher but targets the Internet Explorer browser.

karma-edge-launcher

karma-edge-launcher is a plugin to launch Microsoft Edge for testing with Karma. It provides similar features to karma-chrome-launcher, adapted for the Edge browser.

README

karma-chrome-launcher

Launcher for Google Chrome, Google Chrome Canary and Google Chromium.

Installation

The easiest way is to keep karma-chrome-launcher as a devDependency in your package.json, by running

$ npm i -D karma-chrome-launcher

Configuration

// karma.conf.js
module.exports = function(config) {
  config.set({
    browsers: ['Chrome', 'Chrome_without_security'], // You may use 'ChromeCanary', 'Chromium' or any other supported browser

    // you can define custom flags
    customLaunchers: {
      Chrome_without_security: {
        base: 'Chrome',
        flags: ['--disable-web-security', '--disable-site-isolation-trials']
      }
    }
  })
}

The --user-data-dir is set to a temporary directory but can be overridden on a custom launcher as shown below. One reason to do this is to have a permanent Chrome user data directory inside the project directory to be able to install plugins there (e.g. JetBrains IDE Support plugin).

customLaunchers: {
  Chrome_with_debugging: {
    base: 'Chrome',
    chromeDataDir: path.resolve(__dirname, '.chrome')
  }
}

You can pass list of browsers as a CLI argument too:

$ karma start --browsers Chrome,Chrome_without_security

Headless Chromium with Puppeteer

The Chrome DevTools team created Puppeteer - it will automatically install Chromium for all platforms and contains everything you need to run it from within your CI.

Available Browsers

Note: Headless mode requires a browser version >= 59

• Chrome (CHROME_BIN)
• ChromeHeadless (CHROME_BIN)
• Chromium (CHROMIUM_BIN)
• ChromiumHeadless (CHROMIUM_BIN)
• ChromeCanary (CHROME_CANARY_BIN)
• ChromeCanaryHeadless (CHROME_CANARY_BIN)
• Dartium (DARTIUM_BIN)

Usage

$ npm i -D puppeteer karma-chrome-launcher

// karma.conf.js
process.env.CHROME_BIN = require('puppeteer').executablePath()

module.exports = function(config) {
  config.set({
    browsers: ['ChromeHeadless']
  })
}

For more information on Karma see the homepage.