This is a prototype debugger based on React and Redux.

• npm install - Install Dependencies
• npm run firefox - Start Firefox
• npm start - Start Debugger

Visit http://localhost:8000 in any browser to see the debugger.

If you would like to open a specific Firefox instance or use a specific profile, first make sure it has the appropate flags enabled. Then run the following command and replace <Firefox.app> with your Firefox. For example, nightly would be FirefoxNightly.app.

$ /Applications/<Firefox.app>/Contents/MacOS/firefox-bin -P development --start-debugger-server 6080

You can also press shift+F2 and type "listen" in the command bar in an existing Firefox instance start the debugger server.

The default behavior is to debug Firefox, but we support Chrome as well (this is experimental). To enable this, create a config/local.json file with the contents { "chrome": { "debug": true }} (or add that config to an existing local.json file). Then run Chrome with the following flags:

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --remote-debugging-port=9222 --no-first-run --user-data-dir=/tmp/chrome-dev-profile

The debugger should list Chrome tabs now.

The Debugger is an open source project and we would love your help. We have prepared a contributing guide to help answer some of the common questions.

We're all in Mozilla's IRC channel #devtools on irc.mozilla.org.

As a developer, you most likely want to enable hot reloading. This means you can save any CSS or React file and instantly see changes in the browser without losing any state. To do so, create a local config file a config/local.json with the contents { "hotReloading: true" }.

• npm test - Run tests headlessly
• npm run mocha-server - Run tests in the browser

• npm run cypress - Run tests headlessly
• npm run cypress-intermittents - Runs tests 100 times and writes the output to cypress-run.log
• cypress open - Run tests in the browser

More information.

• npm run lint - Run CSS and JS linter
• npm run lint-css - Run CSS linter
• npm run lint-js - Run JS linter

• npm run test-all - Run unit tests, lints, and integration tests

• npm run storybook - Open Storybook. more info

You can see default config values in config/development.json, and override them by creating a config/local.json file which will be ignored by git.

• hotReloding enables hot reloading of CSS and React
• chrome.debug enable local chrome development
• features.sourceTabs enable editor tabs
• logging.firefoxProtocol log firefox debugger protocol messages

More Information

The profile for the Firefox you are debugging needs to have a few flags switched to make it debuggable. Go to about:config and set these values in the target Firefox:

• devtools.debugger.remote-enabled to true
• devtools.chrome.enabled to true
• devtools.debugger.prompt-connection to false