electron/docs/api/app.md

# app

The `app` module is responsible for controlling the application's life time.

The example of quitting the whole application when the last window is closed:

```javascript
var app = require('app');
app.on('window-all-closed', function() {
  app.quit();
});
```

## Event: will-finish-launching

Emitted when application has done basic startup. On Windows and Linux it is the
same with `ready` event, on OS X this event represents the
`applicationWillFinishLaunching` message of `NSApplication`, usually you would
setup listeners to `open-file` and `open-url` events here, and start the crash
reporter and auto updater.

Under most cases you should just do everything in `ready` event.

## Event: ready

Emitted when Electron has done everything initialization.

## Event: window-all-closed

Emitted when all windows have been closed.

This event is only emitted when the application is not going to quit. If a
user pressed `Cmd + Q`, or the developer called `app.quit()`, Electron would
first try to close all windows and then emit the `will-quit` event, and in
this case the `window-all-closed` would not be emitted.

## Event: before-quit

* `event` Event

Emitted before the application starts closing its windows.
Calling `event.preventDefault()` will prevent the default behaviour, which is
terminating the application.

## Event: will-quit

* `event` Event

Emitted when all windows have been closed and the application will quit.
Calling `event.preventDefault()` will prevent the default behaviour, which is
terminating the application.

See description of `window-all-closed` for the differences between `will-quit`
and it.

## Event: quit

Emitted when application is quitting.

## Event: open-file

* `event` Event
* `path` String

Emitted when user wants to open a file with the application, it usually happens when the application is already opened and then OS wants to reuse the application to open file. But it is also emitted when a file is dropped onto the dock and the application is not yet running. Make sure to liste to open-file very early in your application startup to handle this case (even before the ready event is emitted).

You should call `event.preventDefault()` if you want to handle this event.

## Event: open-url

* `event` Event
* `url` String

Emitted when user wants to open a URL with the application, this URL scheme
must be registered to be opened by your application.

You should call `event.preventDefault()` if you want to handle this event.

## Event: activate-with-no-open-windows

Emitted when the application is activated while there is no opened windows. It
usually happens when user has closed all of application's windows and then
click on the application's dock icon.

## app.quit()

Try to close all windows. The `before-quit` event will first be emitted. If all
windows are successfully closed, the `will-quit` event will be emitted and by
default the application would be terminated.

This method guarantees all `beforeunload` and `unload` handlers are correctly
executed. It is possible that a window cancels the quitting by returning
`false` in `beforeunload` handler.

## app.getPath(name)

* `name` String

Retrieves a path to a special directory or file associated with `name`. On
failure an `Error` would throw.

You can request following paths by the names:

* `home`: User's home directory
* `appData`: Per-user application data directory, by default it is pointed to:
  * `%APPDATA%` on Windows
  * `$XDG_CONFIG_HOME` or `~/.config` on Linux
  * `~/Library/Application Support` on OS X
* `userData`: The directory for storing your app's configuration files, by
  default it is the `appData` directory appended with your app's name
* `cache`: Per-user application cache directory, by default it is pointed to:
  * `%APPDATA%` on Window, which doesn't has a universal place for cache
  * `$XDG_CACHE_HOME` or `~/.cache` on Linux
  * `~/Library/Caches` on OS X
* `userCache`: The directory for placing your app's caches, by default it is the
 `cache` directory appended with your app's name
* `temp`: Temporary directory
* `userDesktop`: The current user's Desktop directory
* `exe`: The current executable file
* `module`: The `libchromiumcontent` library

## app.setPath(name, path)

* `name` String
* `path` String

Overrides the `path` to a special directory or file associated with `name`. if
the path specifies a directory that does not exist, the directory will be
created by this method. On failure an `Error` would throw.

You can only override paths of `name`s  defined in `app.getPath`.

By default web pages' cookies and caches will be stored under `userData`
directory, if you want to change this location, you have to override the
`userData` path before the `ready` event of `app` module gets emitted.

## app.getVersion()

Returns the version of loaded application, if no version is found in
application's `package.json`, the version of current bundle or executable would
be returned.

## app.getName()

Returns current application's name, the name in `package.json` would be
used.

Usually the `name` field of `package.json` is a short lowercased name, according
to the spec of npm modules. So usually you should also specify a `productName`
field, which is your application's full capitalized name, and it will be
preferred over `name` by Electron.

## app.resolveProxy(url, callback)

* `url` URL
* `callback` Function

Resolves the proxy information for `url`, the `callback` would be called with
`callback(proxy)` when the request is done.

## app.addRecentDocument(path)

* `path` String

Adds `path` to recent documents list.

This list is managed by the system, on Windows you can visit the list from task
bar, and on Mac you can visit it from dock menu.

## app.clearRecentDocuments()

Clears the recent documents list.

## app.setUserTasks(tasks)

* `tasks` Array - Array of `Task` objects

Adds `tasks` to the [Tasks][tasks] category of JumpList on Windows.

The `tasks` is an array of `Task` objects in following format:

* `Task` Object
  * `program` String - Path of the program to execute, usually you should
    specify `process.execPath` which opens current program
  * `arguments` String - The arguments of command line when `program` is
    executed
  * `title` String - The string to be displayed in a JumpList
  * `description` String - Description of this task
  * `iconPath` String - The absolute path to an icon to be displayed in a
    JumpList, it can be arbitrary resource file that contains an icon, usually
    you can specify `process.execPath` to show the icon of the program
  * `iconIndex` Integer - The icon index in the icon file. If an icon file
    consists of two or more icons, set this value to identify the icon. If an
    icon file consists of one icon, this value is 0

**Note:** This API is only available on Windows.

## app.commandLine.appendSwitch(switch, [value])

Append a switch [with optional value] to Chromium's command line.

**Note:** This will not affect `process.argv`, and is mainly used by developers
to control some low-level Chromium behaviors.

## app.commandLine.appendArgument(value)

Append an argument to Chromium's command line. The argument will quoted properly.

**Note:** This will not affect `process.argv`.

## app.dock.bounce([type])

* `type` String - Can be `critical` or `informational`, the default is
 `informational`

When `critical` is passed, the dock icon will bounce until either the
application becomes active or the request is canceled.

When `informational` is passed, the dock icon will bounce for one second. The
request, though, remains active until either the application becomes active or
the request is canceled.

An ID representing the request would be returned.

**Note:** This API is only available on Mac.

## app.dock.cancelBounce(id)

* `id` Integer

Cancel the bounce of `id`.

**Note:** This API is only available on Mac.

## app.dock.setBadge(text)

* `text` String

Sets the string to be displayed in the dock’s badging area.

**Note:** This API is only available on Mac.

## app.dock.getBadge()

Returns the badge string of the dock.

**Note:** This API is only available on Mac.

## app.dock.hide()

Hides the dock icon.

**Note:** This API is only available on Mac.

## app.dock.show()

Shows the dock icon.

**Note:** This API is only available on Mac.

## app.dock.setMenu(menu)

* `menu` Menu

Sets the application [dock menu][dock-menu].

**Note:** This API is only available on Mac.

[dock-menu]:https://developer.apple.com/library/mac/documentation/Carbon/Conceptual/customizing_docktile/concepts/dockconcepts.html#//apple_ref/doc/uid/TP30000986-CH2-TPXREF103
[tasks]:http://msdn.microsoft.com/en-us/library/windows/desktop/dd378460(v=vs.85).aspx#tasks