Chrome Launcher

Launch Google Chrome with ease from node.

• Disables many Chrome services that add noise to automated scenarios
• Opens up the browser's remote-debugging-port on an available port
• Automagically locates a Chrome binary to launch
• Uses a fresh Chrome profile for each launch, and cleans itself up on kill()
• Binds Ctrl-C (by default) to terminate the Chrome process
• Exposes a small set of options for configurability over these details

Once launched, interacting with the browser must be done over the devtools protocol, typically via chrome-remote-interface. For many cases Puppeteer is recommended, though it has its own chrome launching mechanism.

Installing

yarn add chrome-launcher

# or with npm:
npm install chrome-launcher

API

.launch([opts])

Launch options

{
  // (optional) remote debugging port number to use. If provided port is already busy, launch() will reject
  // Default: an available port is autoselected
  port: number;

  // (optional) Additional flags to pass to Chrome, for example: ['--headless', '--disable-gpu']
  // See: https://github.com/GoogleChrome/chrome-launcher/blob/master/docs/chrome-flags-for-tools.md
  // Do note, many flags are set by default: https://github.com/GoogleChrome/chrome-launcher/blob/master/src/flags.ts
  chromeFlags: Array<string>;

  // (optional) Additional preferences to be set in Chrome, for example: {'download.default_directory': __dirname}
  // See: https://chromium.googlesource.com/chromium/src/+/main/chrome/common/pref_names.cc
  // Do note, if you set preferences when using your default profile it will overwrite these
  prefs: {[key: string]: Object};

  // (optional) Close the Chrome process on `Ctrl-C`
  // Default: true
  handleSIGINT: boolean;

  // (optional) Explicit path of intended Chrome binary
  // * If this `chromePath` option is defined, it will be used.
  // * Otherwise, the `CHROME_PATH` env variable will be used if set. (`LIGHTHOUSE_CHROMIUM_PATH` is deprecated)
  // * Otherwise, a detected Chrome Canary will be used if found
  // * Otherwise, a detected Chrome (stable) will be used
  chromePath: string;

  // (optional) Chrome profile path to use, if set to `false` then the default profile will be used.
  // By default, a fresh Chrome profile will be created
  userDataDir: string | boolean;

  // (optional) Starting URL to open the browser with
  // Default: `about:blank`
  startingUrl: string;

  // (optional) Logging level
  // Default: 'silent'
  logLevel: 'verbose'|'info'|'error'|'silent';

  // (optional) Flags specific in [flags.ts](src/flags.ts) will not be included.
  // Typically used with the defaultFlags() method and chromeFlags option.
  // Default: false
  ignoreDefaultFlags: boolean;

  // (optional) Interval in ms, which defines how often launcher checks browser port to be ready.
  // Default: 500
  connectionPollInterval: number;

  // (optional) A number of retries, before browser launch considered unsuccessful.
  // Default: 50
  maxConnectionRetries: number;

  // (optional) A dict of environmental key value pairs to pass to the spawned chrome process.
  envVars: {[key: string]: string};
};

Launched chrome interface

.launch().then(chrome => ...

// The remote debugging port exposed by the launched chrome
chrome.port: number;

// Method to kill Chrome (and cleanup the profile folder)
chrome.kill: () => Promise<void>;

// The process id
chrome.pid: number;

// The childProcess object for the launched Chrome
chrome.process: childProcess

ChromeLauncher.Launcher.defaultFlags()

Returns an Array<string> of the default flags Chrome is launched with. Typically used along with the ignoreDefaultFlags and chromeFlags options.

Note: This array will exclude the following flags: --remote-debugging-port --disable-setuid-sandbox --user-data-dir.

ChromeLauncher.Launcher.getInstallations()

Returns an Array<string> of paths to available Chrome installations. When chromePath is not provided to .launch(), the first installation returned from this method is used instead.

Note: This method performs synchronous I/O operations.

.killAll()

Attempts to kill all Chrome instances created with .launch([opts]). Returns a Promise that resolves to an array of errors that occurred while killing instances. If all instances were killed successfully, the array will be empty.

const ChromeLauncher = require('chrome-launcher');

async function cleanup() {
  await ChromeLauncher.killAll();
}

Examples

Launching chrome:

const ChromeLauncher = require('chrome-launcher');

ChromeLauncher.launch({
  startingUrl: 'https://google.com'
}).then(chrome => {
  console.log(`Chrome debugging port running on ${chrome.port}`);
});

Launching headless chrome:

const ChromeLauncher = require('chrome-launcher');

ChromeLauncher.launch({
  startingUrl: 'https://google.com',
  chromeFlags: ['--headless', '--disable-gpu']
}).then(chrome => {
  console.log(`Chrome debugging port running on ${chrome.port}`);
});

Launching with support for extensions and audio:

const ChromeLauncher = require('chrome-launcher');

const newFlags = ChromeLauncher.Launcher.defaultFlags().filter(flag => flag !== '--disable-extensions' && flag !== '--mute-audio');

ChromeLauncher.launch({
  ignoreDefaultFlags: true,
  chromeFlags: newFlags,
}).then(chrome => { ... });

Continuous Integration

In a CI environment like Travis, Chrome may not be installed. If you want to use chrome-launcher, Travis can install Chrome at run time with an addon. Alternatively, you can also install Chrome using the download-chrome.sh script.

Then in .travis.yml, use it like so:

language: node_js
install:
  - yarn install
before_script:
  - export DISPLAY=:99.0
  - export CHROME_PATH="$(pwd)/chrome-linux/chrome"
  - sh -e /etc/init.d/xvfb start
  - sleep 3 # wait for xvfb to boot

addons:
  chrome: stable