# DevTools extension

To make debugging more easy, atom-shell has added basic support for
[Chrome DevTools Extension][devtools-extension].

For most devtools extensions, you can simply download their source codes and use
the `BrowserWindow.addDevToolsExtension` API to load them, the loaded extensions
will be remembered so you don't need to call the API every time when creating
a window.

For example to use the React DevTools Extension, first you need to download its
source code:

```bash
$ cd /some-directory
$ git clone --recursive https://github.com/facebook/react-devtools.git
```

Then you can load it in atom-shell by opening the devtools in arbitray window,
and run this code in the console of devtools:

```javascript
require('remote').require('browser-window').addDevToolsExtension('/some-directory/react-devtools')
```

To unload the extension, you can call `BrowserWindow.removeDevToolsExtension`
API with its name and it will disappear the next time you open the devtools:

```javascript
require('remote').require('browser-window').removeDevToolsExtension('React Developer Tools')
```

## Format of devtools extension

Ideally all devtools extension written for Chrome browser can be loaded by
atom-shell, but they have to be in a plain directory, for those packaged `crx`
extensions, there is no way in atom-shell to load them unless you find a way to
extract them into a directory.

## Background pages

Currently atom-shell doesn't support the background pages of chrome extensions,
so for some devtools extensions that rely on this feature, they may not work
well in atom-shell

## `chrome.*` APIs

Some chrome extensions use `chrome.*` APIs for some features, there is some
effort to implement those APIs in atom-shell to make them work, but we have
only implemented few for now.

So if the devtools extension is using APIs other than `chrome.devtools.*`, it is
very likely to fail, but you can report those extensions in the issues tracker
so we can add support for those APIs.

[devtools-extension]: https://developer.chrome.com/extensions/devtools
