# Chrome DevTools frontend

The client-side of the Chrome DevTools, including all JS & CSS to run the DevTools webapp.

It is available on NPM as the [chrome-devtools-frontend](https://www.npmjs.com/package/chrome-devtools-frontend) package. It's not currently available via CJS or ES2015 modules, so consuming this package in other tools may require [some effort](https://github.com/paulirish/devtools-timeline-model/blob/master/index.js).

#### Package versioning
The version number of the npm package (e.g. `1.0.373466`) refers to the Chromium commit position of latest frontend git commit. It's incremented with every Chromium commit, however the package is updated roughly daily.

### Source code
The frontend is available through a git subtree mirror on [chromium.googlesource.com](https://chromium.googlesource.com/chromium/src/third_party/blink/renderer/devtools/), with a regularly updating GitHub mirror at [github.com/ChromeDevTools/devtools-frontend](https://github.com/ChromeDevTools/devtools-frontend). The codebase's true location is in `third_party/blink/renderer/devtools/` in [Chromium's git repo](https://chromium.googlesource.com/chromium/src/).

### Getting Started

1. Clone the repo
2. Go to repo root and run:  `npm start`
    - This launches Chrome Canary and starts the dev server with 1 command
3. Go to http://localhost:9222#custom=true&experiments=true

> **Power user tips:**
>
> You can customize the port for the dev server: e.g. `PORT=8888 npm start`.
>
> You can also launch chrome and start the server separately:
> - `npm run chrome`
> - `npm run server`
>
> When you start Chrome separately, you can pass extra args to Chrome:
> ```
> npm run chrome -- https://news.ycombinator.com
> ```
> (e.g. this launches Hacker News on startup)
>
> If you want to reset your development profile for Chrome, pass in "--reset-profile":
> ```
> npm start -- --reset-profile
> ```
> *OR*
> ```
> npm run chrome -- --reset-profile
> ```

### Hacking
* DevTools documentation: [devtools.chrome.com](https://devtools.chrome.com)
* [Debugging protocol docs](https://developer.chrome.com/devtools/docs/debugger-protocol) and [Chrome Debugging Protocol Viewer](http://chromedevtools.github.io/debugger-protocol-viewer/)
* [awesome-chrome-devtools](https://github.com/paulirish/awesome-chrome-devtools): recommended tools and resources
* Contributing to DevTools: [bit.ly/devtools-contribution-guide](http://bit.ly/devtools-contribution-guide)

### Useful Commands

#### Simpler npm commands w/ `dtrun`
If you want to run these npm commands anywhere in the chromium repo (e.g. in chromium/src), you'll want to setup our `dtrun` CLI helper.

One-time setup:
```
npm run setup-dtrun
```

Now, you can use any of the following commands by simply doing: `dtrun test`. 

In addition, you no longer need to pass double dashes (e.g. `--`) before you pass in the flags. So you can do: `dtrun test -d inspector/test.html`.

#### `npm run format` 
Formats your code using clang-format

### `npm run format-py`
Formats your Python code using [yapf](https://github.com/google/yapf)

> Note: Yapf is a command line tool. You will have to install this manually, either from PyPi through `pip install yapf` or if you want to enable multiprocessing in Python 2.7, `pip install futures`

#### `npm test`
Builds devtools and runs all inspector/devtools layout tests.

> Note: If you're using a full chromium checkout and compiled content shell in out/Release, then `npm test` uses that. Otherwise, with only a front-end checkout (i.e. cloning from GitHub), then `npm test` will fetch a previously compiled content shell from the cloud (and cache it for future test runs).

#### `npm test` basics
```
# run specific tests
npm test -- inspector/sources inspector/console

# debug a specific test. Any one of:
npm run debug-test inspector/cookie-resource-match.html
npm test -- --debug-devtools inspector/cookie-resource-match.html 
npm test -- -d inspector/cookie-resource-match.html 

# pass in additional flags to the test harness
npm test -- -f --child-processes=16

# ...for example, use a higher test timeout
npm test -- --time-out-ms=6000000 <test_path>
```

> **Tip**: [Learn about the test harness flags](https://chromium.googlesource.com/chromium/src/+/master/docs/testing/layout_tests.md#Test-Harness-Options)

#### `--fetch-content-shell`
```
# If you're using a full chromium checkout and have a compiled content shell, 
# this will fetch a pre-compiled content shell. This is useful if you 
# haven't compiled your content shell recently
npm test -- --fetch-content-shell
```

#### `--target=SUB_DIRECTORY_NAME`
```
# If you're using a build sub-directory that's not out/Release, 
# such as out/Default, then use --target=SUB_DIRECTORY_NAME
npm test -- --target=Default
```
### Development
* All devtools commits: [View the log], [RSS feed] or [@DevToolsCommits] on Twitter
* [All open DevTools tickets] on crbug.com
* File a new DevTools ticket: [new.crbug.com](https://bugs.chromium.org/p/chromium/issues/entry?labels=OS-All,Type-Bug,Pri-2&components=Platform%3EDevTools)
* Code reviews mailing list: [devtools-reviews@chromium.org]

### Getting in touch
* [@ChromeDevTools] on Twitter
* Chrome DevTools mailing list: [groups.google.com/forum/google-chrome-developer-tools](https://groups.google.com/forum/#!forum/google-chrome-developer-tools)

  [devtools-reviews@chromium.org]: https://groups.google.com/a/chromium.org/forum/#!forum/devtools-reviews
  [RSS feed]: https://feeds.peter.sh/chrome-devtools/
  [View the log]: https://chromium.googlesource.com/chromium/src/third_party/blink/renderer/devtools/+log/master
  [@ChromeDevTools]: http://twitter.com/ChromeDevTools
  [@DevToolsCommits]: http://twitter.com/DevToolsCommits
  [all open DevTools tickets]: https://bugs.chromium.org/p/chromium/issues/list?can=2&q=component%3APlatform%3EDevTools&sort=&groupby=&colspec=ID+Stars+Owner+Summary+Modified+Opened