56 KiB
Executable File
app
Control your application's event lifecycle.
Process: Main
The following example shows how to quit the application when the last window is closed:
const { app } = require('electron')
app.on('window-all-closed', () => {
app.quit()
})
Events
The app
object emits the following events:
Event: 'will-finish-launching'
Emitted when the application has finished basic startup. On Windows and Linux,
the will-finish-launching
event is the same as the ready
event; on macOS,
this event represents the applicationWillFinishLaunching
notification of
NSApplication
. You would usually set up listeners for the open-file
and
open-url
events here, and start the crash reporter and auto updater.
In most cases, you should do everything in the ready
event handler.
Event: 'ready'
Returns:
event
EventlaunchInfo
Record<string, any> | NotificationResponse macOS
Emitted once, when Electron has finished initializing. On macOS, launchInfo
holds the userInfo
of the NSUserNotification
or information from
UNNotificationResponse
that was used to open the
application, if it was launched from Notification Center. You can also call
app.isReady()
to check if this event has already fired and app.whenReady()
to get a Promise that is fulfilled when Electron is initialized.
Event: 'window-all-closed'
Emitted when all windows have been closed.
If you do not subscribe to this event and all windows are closed, the default
behavior is to quit the app; however, if you subscribe, you control whether the
app quits or not. If the user pressed Cmd + Q
, or the developer called
app.quit()
, Electron will first try to close all the windows and then emit the
will-quit
event, and in this case the window-all-closed
event would not be
emitted.
Event: 'before-quit'
Returns:
event
Event
Emitted before the application starts closing its windows.
Calling event.preventDefault()
will prevent the default behavior, which is
terminating the application.
Note: If application quit was initiated by autoUpdater.quitAndInstall()
,
then before-quit
is emitted after emitting close
event on all windows and
closing them.
Note: On Windows, this event will not be emitted if the app is closed due to a shutdown/restart of the system or a user logout.
Event: 'will-quit'
Returns:
event
Event
Emitted when all windows have been closed and the application will quit.
Calling event.preventDefault()
will prevent the default behavior, which is
terminating the application.
See the description of the window-all-closed
event for the differences between
the will-quit
and window-all-closed
events.
Note: On Windows, this event will not be emitted if the app is closed due to a shutdown/restart of the system or a user logout.
Event: 'quit'
Returns:
event
EventexitCode
Integer
Emitted when the application is quitting.
Note: On Windows, this event will not be emitted if the app is closed due to a shutdown/restart of the system or a user logout.
Event: 'open-file' macOS
Returns:
event
Eventpath
String
Emitted when the user wants to open a file with the application. The open-file
event is usually emitted when the application is already open and the OS wants
to reuse the application to open the file. open-file
is also emitted when a
file is dropped onto the dock and the application is not yet running. Make sure
to listen for the open-file
event 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.
On Windows, you have to parse process.argv
(in the main process) to get the
filepath.
Event: 'open-url' macOS
Returns:
event
Eventurl
String
Emitted when the user wants to open a URL with the application. Your application's
Info.plist
file must define the URL scheme within the CFBundleURLTypes
key, and
set NSPrincipalClass
to AtomApplication
.
You should call event.preventDefault()
if you want to handle this event.
Event: 'activate' macOS
Returns:
event
EventhasVisibleWindows
Boolean
Emitted when the application is activated. Various actions can trigger this event, such as launching the application for the first time, attempting to re-launch the application when it's already running, or clicking on the application's dock or taskbar icon.
Event: 'did-become-active' macOS
Returns:
event
Event
Emitted when mac application become active. Difference from activate
event is
that did-become-active
is emitted every time the app becomes active, not only
when Dock icon is clicked or application is re-launched.
Event: 'continue-activity' macOS
Returns:
event
Eventtype
String - A string identifying the activity. Maps toNSUserActivity.activityType
.userInfo
unknown - Contains app-specific state stored by the activity on another device.
Emitted during Handoff when an activity from a different device wants
to be resumed. You should call event.preventDefault()
if you want to handle
this event.
A user activity can be continued only in an app that has the same developer Team
ID as the activity's source app and that supports the activity's type.
Supported activity types are specified in the app's Info.plist
under the
NSUserActivityTypes
key.
Event: 'will-continue-activity' macOS
Returns:
event
Eventtype
String - A string identifying the activity. Maps toNSUserActivity.activityType
.
Emitted during Handoff before an activity from a different device wants
to be resumed. You should call event.preventDefault()
if you want to handle
this event.
Event: 'continue-activity-error' macOS
Returns:
event
Eventtype
String - A string identifying the activity. Maps toNSUserActivity.activityType
.error
String - A string with the error's localized description.
Emitted during Handoff when an activity from a different device fails to be resumed.
Event: 'activity-was-continued' macOS
Returns:
event
Eventtype
String - A string identifying the activity. Maps toNSUserActivity.activityType
.userInfo
unknown - Contains app-specific state stored by the activity.
Emitted during Handoff after an activity from this device was successfully resumed on another one.
Event: 'update-activity-state' macOS
Returns:
event
Eventtype
String - A string identifying the activity. Maps toNSUserActivity.activityType
.userInfo
unknown - Contains app-specific state stored by the activity.
Emitted when Handoff is about to be resumed on another device. If you need to update the state to be transferred, you should call event.preventDefault()
immediately, construct a new userInfo
dictionary and call app.updateCurrentActivity()
in a timely manner. Otherwise, the operation will fail and continue-activity-error
will be called.
Event: 'new-window-for-tab' macOS
Returns:
event
Event
Emitted when the user clicks the native macOS new tab button. The new
tab button is only visible if the current BrowserWindow
has a
tabbingIdentifier
Event: 'browser-window-blur'
Returns:
event
Eventwindow
BrowserWindow
Emitted when a browserWindow gets blurred.
Event: 'browser-window-focus'
Returns:
event
Eventwindow
BrowserWindow
Emitted when a browserWindow gets focused.
Event: 'browser-window-created'
Returns:
event
Eventwindow
BrowserWindow
Emitted when a new browserWindow is created.
Event: 'web-contents-created'
Returns:
event
EventwebContents
WebContents
Emitted when a new webContents is created.
Event: 'certificate-error'
Returns:
event
EventwebContents
WebContentsurl
Stringerror
String - The error codecertificate
Certificatecallback
FunctionisTrusted
Boolean - Whether to consider the certificate as trusted
Emitted when failed to verify the certificate
for url
, to trust the
certificate you should prevent the default behavior with
event.preventDefault()
and call callback(true)
.
const { app } = require('electron')
app.on('certificate-error', (event, webContents, url, error, certificate, callback) => {
if (url === 'https://github.com') {
// Verification logic.
event.preventDefault()
callback(true)
} else {
callback(false)
}
})
Event: 'select-client-certificate'
Returns:
event
EventwebContents
WebContentsurl
URLcertificateList
Certificate[]callback
Functioncertificate
Certificate (optional)
Emitted when a client certificate is requested.
The url
corresponds to the navigation entry requesting the client certificate
and callback
can be called with an entry filtered from the list. Using
event.preventDefault()
prevents the application from using the first
certificate from the store.
const { app } = require('electron')
app.on('select-client-certificate', (event, webContents, url, list, callback) => {
event.preventDefault()
callback(list[0])
})
Event: 'login'
Returns:
event
EventwebContents
WebContentsauthenticationResponseDetails
Objecturl
URL
authInfo
ObjectisProxy
Booleanscheme
Stringhost
Stringport
Integerrealm
String
callback
Functionusername
String (optional)password
String (optional)
Emitted when webContents
wants to do basic auth.
The default behavior is to cancel all authentications. To override this you
should prevent the default behavior with event.preventDefault()
and call
callback(username, password)
with the credentials.
const { app } = require('electron')
app.on('login', (event, webContents, details, authInfo, callback) => {
event.preventDefault()
callback('username', 'secret')
})
If callback
is called without a username or password, the authentication
request will be cancelled and the authentication error will be returned to the
page.
Event: 'gpu-info-update'
Emitted whenever there is a GPU info update.
Event: 'gpu-process-crashed' Deprecated
Returns:
event
Eventkilled
Boolean
Emitted when the GPU process crashes or is killed.
Deprecated: This event is superceded by the child-process-gone
event
which contains more information about why the child process disappeared. It
isn't always because it crashed. The killed
boolean can be replaced by
checking reason === 'killed'
when you switch to that event.
Event: 'renderer-process-crashed' Deprecated
Returns:
event
EventwebContents
WebContentskilled
Boolean
Emitted when the renderer process of webContents
crashes or is killed.
Deprecated: This event is superceded by the render-process-gone
event
which contains more information about why the render process disappeared. It
isn't always because it crashed. The killed
boolean can be replaced by
checking reason === 'killed'
when you switch to that event.
Event: 'render-process-gone'
Returns:
event
EventwebContents
WebContentsdetails
Objectreason
String - The reason the render process is gone. Possible values:clean-exit
- Process exited with an exit code of zeroabnormal-exit
- Process exited with a non-zero exit codekilled
- Process was sent a SIGTERM or otherwise killed externallycrashed
- Process crashedoom
- Process ran out of memorylaunch-failed
- Process never successfully launchedintegrity-failure
- Windows code integrity checks failed
exitCode
Integer - The exit code of the process, unlessreason
islaunch-failed
, in which caseexitCode
will be a platform-specific launch failure error code.
Emitted when the renderer process unexpectedly disappears. This is normally because it was crashed or killed.
Event: 'child-process-gone'
Returns:
event
Eventdetails
Objecttype
String - Process type. One of the following values:Utility
Zygote
Sandbox helper
GPU
Pepper Plugin
Pepper Plugin Broker
Unknown
reason
String - The reason the child process is gone. Possible values:clean-exit
- Process exited with an exit code of zeroabnormal-exit
- Process exited with a non-zero exit codekilled
- Process was sent a SIGTERM or otherwise killed externallycrashed
- Process crashedoom
- Process ran out of memorylaunch-failed
- Process never successfully launchedintegrity-failure
- Windows code integrity checks failed
exitCode
Number - The exit code for the process (e.g. status from waitpid if on posix, from GetExitCodeProcess on Windows).serviceName
String (optional) - The non-localized name of the process.name
String (optional) - The name of the process. Examples for utility:Audio Service
,Content Decryption Module Service
,Network Service
,Video Capture
, etc.
Emitted when the child process unexpectedly disappears. This is normally because it was crashed or killed. It does not include renderer processes.
Event: 'accessibility-support-changed' macOS Windows
Returns:
event
EventaccessibilitySupportEnabled
Boolean -true
when Chrome's accessibility support is enabled,false
otherwise.
Emitted when Chrome's accessibility support changes. This event fires when assistive technologies, such as screen readers, are enabled or disabled. See https://www.chromium.org/developers/design-documents/accessibility for more details.
Event: 'session-created'
Returns:
session
Session
Emitted when Electron has created a new session
.
const { app } = require('electron')
app.on('session-created', (session) => {
console.log(session)
})
Event: 'second-instance'
Returns:
event
Eventargv
String[] - An array of the second instance's command line argumentsworkingDirectory
String - The second instance's working directory
This event will be emitted inside the primary instance of your application
when a second instance has been executed and calls app.requestSingleInstanceLock()
.
argv
is an Array of the second instance's command line arguments,
and workingDirectory
is its current working directory. Usually
applications respond to this by making their primary window focused and
non-minimized.
Note: If the second instance is started by a different user than the first, the argv
array will not include the arguments.
This event is guaranteed to be emitted after the ready
event of app
gets emitted.
Note: Extra command line arguments might be added by Chromium,
such as --original-process-start-time
.
Event: 'desktop-capturer-get-sources'
Returns:
event
EventwebContents
WebContents
Emitted when desktopCapturer.getSources()
is called in the renderer process of webContents
.
Calling event.preventDefault()
will make it return empty sources.
Methods
The app
object has the following methods:
Note: Some methods are only available on specific operating systems and are labeled as such.
app.quit()
Try to close all windows. The before-quit
event will be emitted first. If all
windows are successfully closed, the will-quit
event will be emitted and by
default the application will terminate.
This method guarantees that all beforeunload
and unload
event handlers are
correctly executed. It is possible that a window cancels the quitting by
returning false
in the beforeunload
event handler.
app.exit([exitCode])
exitCode
Integer (optional)
Exits immediately with exitCode
. exitCode
defaults to 0.
All windows will be closed immediately without asking the user, and the before-quit
and will-quit
events will not be emitted.
app.relaunch([options])
options
Object (optional)args
String[] (optional)execPath
String (optional)
Relaunches the app when current instance exits.
By default, the new instance will use the same working directory and command line
arguments with current instance. When args
is specified, the args
will be
passed as command line arguments instead. When execPath
is specified, the
execPath
will be executed for relaunch instead of current app.
Note that this method does not quit the app when executed, you have to call
app.quit
or app.exit
after calling app.relaunch
to make the app restart.
When app.relaunch
is called for multiple times, multiple instances will be
started after current instance exited.
An example of restarting current instance immediately and adding a new command line argument to the new instance:
const { app } = require('electron')
app.relaunch({ args: process.argv.slice(1).concat(['--relaunch']) })
app.exit(0)
app.isReady()
Returns Boolean
- true
if Electron has finished initializing, false
otherwise.
See also app.whenReady()
.
app.whenReady()
Returns Promise<void>
- fulfilled when Electron is initialized.
May be used as a convenient alternative to checking app.isReady()
and subscribing to the ready
event if the app is not ready yet.
app.focus([options])
options
Object (optional)steal
Boolean macOS - Make the receiver the active app even if another app is currently active.
On Linux, focuses on the first visible window. On macOS, makes the application the active app. On Windows, focuses on the application's first window.
You should seek to use the steal
option as sparingly as possible.
app.hide()
macOS
Hides all application windows without minimizing them.
app.show()
macOS
Shows application windows after they were hidden. Does not automatically focus them.
app.setAppLogsPath([path])
path
String (optional) - A custom path for your logs. Must be absolute.
Sets or creates a directory your app's logs which can then be manipulated with app.getPath()
or app.setPath(pathName, newPath)
.
Calling app.setAppLogsPath()
without a path
parameter will result in this directory being set to ~/Library/Logs/YourAppName
on macOS, and inside the userData
directory on Linux and Windows.
app.getAppPath()
Returns String
- The current application directory.
app.getPath(name)
name
String - You can request the following paths by the name:home
User's home directory.appData
Per-user application data directory, which by default points to:%APPDATA%
on Windows$XDG_CONFIG_HOME
or~/.config
on Linux~/Library/Application Support
on macOS
userData
The directory for storing your app's configuration files, which by default it is theappData
directory appended with your app's name.cache
temp
Temporary directory.exe
The current executable file.module
Thelibchromiumcontent
library.desktop
The current user's Desktop directory.documents
Directory for a user's "My Documents".downloads
Directory for a user's downloads.music
Directory for a user's music.pictures
Directory for a user's pictures.videos
Directory for a user's videos.recent
Directory for the user's recent files (Windows only).logs
Directory for your app's log folder.crashDumps
Directory where crash dumps are stored.
Returns String
- A path to a special directory or file associated with name
. On
failure, an Error
is thrown.
If app.getPath('logs')
is called without called app.setAppLogsPath()
being called first, a default log directory will be created equivalent to calling app.setAppLogsPath()
without a path
parameter.
app.getFileIcon(path[, options])
path
Stringoptions
Object (optional)size
Stringsmall
- 16x16normal
- 32x32large
- 48x48 on Linux, 32x32 on Windows, unsupported on macOS.
Returns Promise<NativeImage>
- fulfilled with the app's icon, which is a NativeImage.
Fetches a path's associated icon.
On Windows, there a 2 kinds of icons:
- Icons associated with certain file extensions, like
.mp3
,.png
, etc. - Icons inside the file itself, like
.exe
,.dll
,.ico
.
On Linux and macOS, icons depend on the application associated with file mime type.
app.setPath(name, path)
name
Stringpath
String
Overrides the path
to a special directory or file associated with name
.
If the path specifies a directory that does not exist, an Error
is thrown.
In that case, the directory should be created with fs.mkdirSync
or similar.
You can only override paths of a name
defined in app.getPath
.
By default, web pages' cookies and caches will be stored under the userData
directory. If you want to change this location, you have to override the
userData
path before the ready
event of the app
module is emitted.
app.getVersion()
Returns String
- The version of the loaded application. If no version is found in the
application's package.json
file, the version of the current bundle or
executable is returned.
app.getName()
Returns String
- The current application's name, which is the name in the application's
package.json
file.
Usually the name
field of package.json
is a short lowercase name, according
to the npm modules spec. You should usually also specify a productName
field, which is your application's full capitalized name, and which will be
preferred over name
by Electron.
app.setName(name)
name
String
Overrides the current application's name.
Note: This function overrides the name used internally by Electron; it does not affect the name that the OS uses.
app.getLocale()
Returns String
- The current application locale, fetched using Chromium's l10n_util
library.
Possible return values are documented here.
To set the locale, you'll want to use a command line switch at app startup, which may be found here.
Note: When distributing your packaged app, you have to also ship the
locales
folder.
Note: On Windows, you have to call it after the ready
events gets emitted.
app.getLocaleCountryCode()
Returns String
- User operating system's locale two-letter ISO 3166 country code. The value is taken from native OS APIs.
Note: When unable to detect locale country code, it returns empty string.
app.addRecentDocument(path)
macOS Windows
path
String
Adds path
to the recent documents list.
This list is managed by the OS. On Windows, you can visit the list from the task bar, and on macOS, you can visit it from dock menu.
app.clearRecentDocuments()
macOS Windows
Clears the recent documents list.
app.setAsDefaultProtocolClient(protocol[, path, args])
protocol
String - The name of your protocol, without://
. For example, if you want your app to handleelectron://
links, call this method withelectron
as the parameter.path
String (optional) Windows - The path to the Electron executable. Defaults toprocess.execPath
args
String[] (optional) Windows - Arguments passed to the executable. Defaults to an empty array
Returns Boolean
- Whether the call succeeded.
Sets the current executable as the default handler for a protocol (aka URI
scheme). It allows you to integrate your app deeper into the operating system.
Once registered, all links with your-protocol://
will be opened with the
current executable. The whole link, including protocol, will be passed to your
application as a parameter.
Note: On macOS, you can only register protocols that have been added to
your app's info.plist
, which cannot be modified at runtime. However, you can
change the file during build time via Electron Forge,
Electron Packager, or by editing info.plist
with a text
editor. Please refer to Apple's documentation for details.
Note: In a Windows Store environment (when packaged as an appx
) this API
will return true
for all calls but the registry key it sets won't be accessible
by other applications. In order to register your Windows Store application
as a default protocol handler you must declare the protocol in your manifest.
The API uses the Windows Registry and LSSetDefaultHandlerForURLScheme
internally.
app.removeAsDefaultProtocolClient(protocol[, path, args])
macOS Windows
protocol
String - The name of your protocol, without://
.path
String (optional) Windows - Defaults toprocess.execPath
args
String[] (optional) Windows - Defaults to an empty array
Returns Boolean
- Whether the call succeeded.
This method checks if the current executable as the default handler for a protocol (aka URI scheme). If so, it will remove the app as the default handler.
app.isDefaultProtocolClient(protocol[, path, args])
protocol
String - The name of your protocol, without://
.path
String (optional) Windows - Defaults toprocess.execPath
args
String[] (optional) Windows - Defaults to an empty array
Returns Boolean
- Whether the current executable is the default handler for a
protocol (aka URI scheme).
Note: On macOS, you can use this method to check if the app has been
registered as the default protocol handler for a protocol. You can also verify
this by checking ~/Library/Preferences/com.apple.LaunchServices.plist
on the
macOS machine. Please refer to
Apple's documentation for details.
The API uses the Windows Registry and LSCopyDefaultHandlerForURLScheme
internally.
app.getApplicationNameForProtocol(url)
url
String - a URL with the protocol name to check. Unlike the other methods in this family, this accepts an entire URL, including://
at a minimum (e.g.https://
).
Returns String
- Name of the application handling the protocol, or an empty
string if there is no handler. For instance, if Electron is the default
handler of the URL, this could be Electron
on Windows and Mac. However,
don't rely on the precise format which is not guaranteed to remain unchanged.
Expect a different format on Linux, possibly with a .desktop
suffix.
This method returns the application name of the default handler for the protocol (aka URI scheme) of a URL.
app.getApplicationInfoForProtocol(url)
macOS Windows
url
String - a URL with the protocol name to check. Unlike the other methods in this family, this accepts an entire URL, including://
at a minimum (e.g.https://
).
Returns Promise<Object>
- Resolve with an object containing the following:
icon
NativeImage - the display icon of the app handling the protocol.path
String - installation path of the app handling the protocol.name
String - display name of the app handling the protocol.
This method returns a promise that contains the application name, icon and path of the default handler for the protocol (aka URI scheme) of a URL.
app.setUserTasks(tasks)
Windows
tasks
Task[] - Array ofTask
objects
Adds tasks
to the Tasks category of the Jump List on Windows.
tasks
is an array of Task
objects.
Returns Boolean
- Whether the call succeeded.
Note: If you'd like to customize the Jump List even more use
app.setJumpList(categories)
instead.
app.getJumpListSettings()
Windows
Returns Object
:
minItems
Integer - The minimum number of items that will be shown in the Jump List (for a more detailed description of this value see the MSDN docs).removedItems
JumpListItem[] - Array ofJumpListItem
objects that correspond to items that the user has explicitly removed from custom categories in the Jump List. These items must not be re-added to the Jump List in the next call toapp.setJumpList()
, Windows will not display any custom category that contains any of the removed items.
app.setJumpList(categories)
Windows
categories
JumpListCategory[] |null
- Array ofJumpListCategory
objects.
Sets or removes a custom Jump List for the application, and returns one of the following strings:
ok
- Nothing went wrong.error
- One or more errors occurred, enable runtime logging to figure out the likely cause.invalidSeparatorError
- An attempt was made to add a separator to a custom category in the Jump List. Separators are only allowed in the standardTasks
category.fileTypeRegistrationError
- An attempt was made to add a file link to the Jump List for a file type the app isn't registered to handle.customCategoryAccessDeniedError
- Custom categories can't be added to the Jump List due to user privacy or group policy settings.
If categories
is null
the previously set custom Jump List (if any) will be
replaced by the standard Jump List for the app (managed by Windows).
Note: If a JumpListCategory
object has neither the type
nor the name
property set then its type
is assumed to be tasks
. If the name
property
is set but the type
property is omitted then the type
is assumed to be
custom
.
Note: Users can remove items from custom categories, and Windows will not
allow a removed item to be added back into a custom category until after
the next successful call to app.setJumpList(categories)
. Any attempt to
re-add a removed item to a custom category earlier than that will result in the
entire custom category being omitted from the Jump List. The list of removed
items can be obtained using app.getJumpListSettings()
.
Note: The maximum length of a Jump List item's description
property is
260 characters. Beyond this limit, the item will not be added to the Jump
List, nor will it be displayed.
Here's a very simple example of creating a custom Jump List:
const { app } = require('electron')
app.setJumpList([
{
type: 'custom',
name: 'Recent Projects',
items: [
{ type: 'file', path: 'C:\\Projects\\project1.proj' },
{ type: 'file', path: 'C:\\Projects\\project2.proj' }
]
},
{ // has a name so `type` is assumed to be "custom"
name: 'Tools',
items: [
{
type: 'task',
title: 'Tool A',
program: process.execPath,
args: '--run-tool-a',
icon: process.execPath,
iconIndex: 0,
description: 'Runs Tool A'
},
{
type: 'task',
title: 'Tool B',
program: process.execPath,
args: '--run-tool-b',
icon: process.execPath,
iconIndex: 0,
description: 'Runs Tool B'
}
]
},
{ type: 'frequent' },
{ // has no name and no type so `type` is assumed to be "tasks"
items: [
{
type: 'task',
title: 'New Project',
program: process.execPath,
args: '--new-project',
description: 'Create a new project.'
},
{ type: 'separator' },
{
type: 'task',
title: 'Recover Project',
program: process.execPath,
args: '--recover-project',
description: 'Recover Project'
}
]
}
])
app.requestSingleInstanceLock()
Returns Boolean
The return value of this method indicates whether or not this instance of your application successfully obtained the lock. If it failed to obtain the lock, you can assume that another instance of your application is already running with the lock and exit immediately.
I.e. This method returns true
if your process is the primary instance of your
application and your app should continue loading. It returns false
if your
process should immediately quit as it has sent its parameters to another
instance that has already acquired the lock.
On macOS, the system enforces single instance automatically when users try to open
a second instance of your app in Finder, and the open-file
and open-url
events will be emitted for that. However when users start your app in command
line, the system's single instance mechanism will be bypassed, and you have to
use this method to ensure single instance.
An example of activating the window of primary instance when a second instance starts:
const { app } = require('electron')
let myWindow = null
const gotTheLock = app.requestSingleInstanceLock()
if (!gotTheLock) {
app.quit()
} else {
app.on('second-instance', (event, commandLine, workingDirectory) => {
// Someone tried to run a second instance, we should focus our window.
if (myWindow) {
if (myWindow.isMinimized()) myWindow.restore()
myWindow.focus()
}
})
// Create myWindow, load the rest of the app, etc...
app.whenReady().then(() => {
myWindow = createWindow()
})
}
app.hasSingleInstanceLock()
Returns Boolean
This method returns whether or not this instance of your app is currently
holding the single instance lock. You can request the lock with
app.requestSingleInstanceLock()
and release with
app.releaseSingleInstanceLock()
app.releaseSingleInstanceLock()
Releases all locks that were created by requestSingleInstanceLock
. This will
allow multiple instances of the application to once again run side by side.
app.setUserActivity(type, userInfo[, webpageURL])
macOS
type
String - Uniquely identifies the activity. Maps toNSUserActivity.activityType
.userInfo
any - App-specific state to store for use by another device.webpageURL
String (optional) - The webpage to load in a browser if no suitable app is installed on the resuming device. The scheme must behttp
orhttps
.
Creates an NSUserActivity
and sets it as the current activity. The activity
is eligible for Handoff to another device afterward.
app.getCurrentActivityType()
macOS
Returns String
- The type of the currently running activity.
app.invalidateCurrentActivity()
macOS
Invalidates the current Handoff user activity.
app.resignCurrentActivity()
macOS
Marks the current Handoff user activity as inactive without invalidating it.
app.updateCurrentActivity(type, userInfo)
macOS
type
String - Uniquely identifies the activity. Maps toNSUserActivity.activityType
.userInfo
any - App-specific state to store for use by another device.
Updates the current activity if its type matches type
, merging the entries from
userInfo
into its current userInfo
dictionary.
app.setAppUserModelId(id)
Windows
id
String
Changes the Application User Model ID to id
.
app.setActivationPolicy(policy)
macOS
policy
String - Can be 'regular', 'accessory', or 'prohibited'.
Sets the activation policy for a given app.
Activation policy types:
- 'regular' - The application is an ordinary app that appears in the Dock and may have a user interface.
- 'accessory' - The application doesn’t appear in the Dock and doesn’t have a menu bar, but it may be activated programmatically or by clicking on one of its windows.
- 'prohibited' - The application doesn’t appear in the Dock and may not create windows or be activated.
app.importCertificate(options, callback)
Linux
options
Objectcertificate
String - Path for the pkcs12 file.password
String - Passphrase for the certificate.
callback
Functionresult
Integer - Result of import.
Imports the certificate in pkcs12 format into the platform certificate store.
callback
is called with the result
of import operation, a value of 0
indicates success while any other value indicates failure according to Chromium net_error_list.
app.disableHardwareAcceleration()
Disables hardware acceleration for current app.
This method can only be called before app is ready.
app.disableDomainBlockingFor3DAPIs()
By default, Chromium disables 3D APIs (e.g. WebGL) until restart on a per domain basis if the GPU processes crashes too frequently. This function disables that behavior.
This method can only be called before app is ready.
app.getAppMetrics()
Returns ProcessMetric[]
: Array of ProcessMetric
objects that correspond to memory and CPU usage statistics of all the processes associated with the app.
app.getGPUFeatureStatus()
Returns GPUFeatureStatus
- The Graphics Feature Status from chrome://gpu/
.
Note: This information is only usable after the gpu-info-update
event is emitted.
app.getGPUInfo(infoType)
infoType
String - Can bebasic
orcomplete
.
Returns Promise<unknown>
For infoType
equal to complete
:
Promise is fulfilled with Object
containing all the GPU Information as in chromium's GPUInfo object. This includes the version and driver information that's shown on chrome://gpu
page.
For infoType
equal to basic
:
Promise is fulfilled with Object
containing fewer attributes than when requested with complete
. Here's an example of basic response:
{
auxAttributes:
{
amdSwitchable: true,
canSupportThreadedTextureMailbox: false,
directComposition: false,
directRendering: true,
glResetNotificationStrategy: 0,
inProcessGpu: true,
initializationTime: 0,
jpegDecodeAcceleratorSupported: false,
optimus: false,
passthroughCmdDecoder: false,
sandboxed: false,
softwareRendering: false,
supportsOverlays: false,
videoDecodeAcceleratorFlags: 0
},
gpuDevice:
[{ active: true, deviceId: 26657, vendorId: 4098 },
{ active: false, deviceId: 3366, vendorId: 32902 }],
machineModelName: 'MacBookPro',
machineModelVersion: '11.5'
}
Using basic
should be preferred if only basic information like vendorId
or driverId
is needed.
app.setBadgeCount([count])
Linux macOS
count
Integer (optional) - If a value is provided, set the badge to the provided value otherwise, on macOS, display a plain white dot (e.g. unknown number of notifications). On Linux, if a value is not provided the badge will not display.
Returns Boolean
- Whether the call succeeded.
Sets the counter badge for current app. Setting the count to 0
will hide the
badge.
On macOS, it shows on the dock icon. On Linux, it only works for Unity launcher.
Note: Unity launcher requires the existence of a .desktop
file to work,
for more information please read Desktop Environment Integration.
app.getBadgeCount()
Linux macOS
Returns Integer
- The current value displayed in the counter badge.
app.isUnityRunning()
Linux
Returns Boolean
- Whether the current desktop environment is Unity launcher.
app.getLoginItemSettings([options])
macOS Windows
options
Object (optional)path
String (optional) Windows - The executable path to compare against. Defaults toprocess.execPath
.args
String[] (optional) Windows - The command-line arguments to compare against. Defaults to an empty array.
If you provided path
and args
options to app.setLoginItemSettings
, then you
need to pass the same arguments here for openAtLogin
to be set correctly.
Returns Object
:
openAtLogin
Boolean -true
if the app is set to open at login.openAsHidden
Boolean macOS -true
if the app is set to open as hidden at login. This setting is not available on MAS builds.wasOpenedAtLogin
Boolean macOS -true
if the app was opened at login automatically. This setting is not available on MAS builds.wasOpenedAsHidden
Boolean macOS -true
if the app was opened as a hidden login item. This indicates that the app should not open any windows at startup. This setting is not available on MAS builds.restoreState
Boolean macOS -true
if the app was opened as a login item that should restore the state from the previous session. This indicates that the app should restore the windows that were open the last time the app was closed. This setting is not available on MAS builds.executableWillLaunchAtLogin
Boolean Windows -true
if app is set to open at login and its run key is not deactivated. This differs fromopenAtLogin
as it ignores theargs
option, this property will be true if the given executable would be launched at login with any arguments.launchItems
Object[] Windowsname
String Windows - name value of a registry entry.path
String Windows - The executable to an app that corresponds to a registry entry.args
String[] Windows - the command-line arguments to pass to the executable.scope
String Windows - one ofuser
ormachine
. Indicates whether the registry entry is underHKEY_CURRENT USER
orHKEY_LOCAL_MACHINE
.enabled
Boolean Windows -true
if the app registry key is startup approved and therefore shows asenabled
in Task Manager and Windows settings.
app.setLoginItemSettings(settings)
macOS Windows
settings
ObjectopenAtLogin
Boolean (optional) -true
to open the app at login,false
to remove the app as a login item. Defaults tofalse
.openAsHidden
Boolean (optional) macOS -true
to open the app as hidden. Defaults tofalse
. The user can edit this setting from the System Preferences soapp.getLoginItemSettings().wasOpenedAsHidden
should be checked when the app is opened to know the current value. This setting is not available on MAS builds.path
String (optional) Windows - The executable to launch at login. Defaults toprocess.execPath
.args
String[] (optional) Windows - The command-line arguments to pass to the executable. Defaults to an empty array. Take care to wrap paths in quotes.enabled
Boolean (optional) Windows -true
will change the startup approved registry key andenable / disable
the App in Task Manager and Windows Settings. Defaults totrue
.name
String (optional) Windows - value name to write into registry. Defaults to the app's AppUserModelId(). Set the app's login item settings.
To work with Electron's autoUpdater
on Windows, which uses Squirrel,
you'll want to set the launch path to Update.exe, and pass arguments that specify your
application name. For example:
const appFolder = path.dirname(process.execPath)
const updateExe = path.resolve(appFolder, '..', 'Update.exe')
const exeName = path.basename(process.execPath)
app.setLoginItemSettings({
openAtLogin: true,
path: updateExe,
args: [
'--processStart', `"${exeName}"`,
'--process-start-args', `"--hidden"`
]
})
app.isAccessibilitySupportEnabled()
macOS Windows
Returns Boolean
- true
if Chrome's accessibility support is enabled,
false
otherwise. This API will return true
if the use of assistive
technologies, such as screen readers, has been detected. See
https://www.chromium.org/developers/design-documents/accessibility for more
details.
app.setAccessibilitySupportEnabled(enabled)
macOS Windows
enabled
Boolean - Enable or disable accessibility tree rendering
Manually enables Chrome's accessibility support, allowing to expose accessibility switch to users in application settings. See Chromium's accessibility docs for more details. Disabled by default.
This API must be called after the ready
event is emitted.
Note: Rendering accessibility tree can significantly affect the performance of your app. It should not be enabled by default.
app.showAboutPanel()
Show the app's about panel options. These options can be overridden with app.setAboutPanelOptions(options)
.
app.setAboutPanelOptions(options)
options
ObjectapplicationName
String (optional) - The app's name.applicationVersion
String (optional) - The app's version.copyright
String (optional) - Copyright information.version
String (optional) macOS - The app's build version number.credits
String (optional) macOS Windows - Credit information.authors
String[] (optional) Linux - List of app authors.website
String (optional) Linux - The app's website.iconPath
String (optional) Linux Windows - Path to the app's icon in a JPEG or PNG file format. On Linux, will be shown as 64x64 pixels while retaining aspect ratio.
Set the about panel options. This will override the values defined in the app's .plist
file on macOS. See the Apple docs for more details. On Linux, values must be set in order to be shown; there are no defaults.
If you do not set credits
but still wish to surface them in your app, AppKit will look for a file named "Credits.html", "Credits.rtf", and "Credits.rtfd", in that order, in the bundle returned by the NSBundle class method main. The first file found is used, and if none is found, the info area is left blank. See Apple documentation for more information.
app.isEmojiPanelSupported()
Returns Boolean
- whether or not the current OS version allows for native emoji pickers.
app.showEmojiPanel()
macOS Windows
Show the platform's native emoji picker.
app.startAccessingSecurityScopedResource(bookmarkData)
mas
bookmarkData
String - The base64 encoded security scoped bookmark data returned by thedialog.showOpenDialog
ordialog.showSaveDialog
methods.
Returns Function
- This function must be called once you have finished accessing the security scoped file. If you do not remember to stop accessing the bookmark, kernel resources will be leaked and your app will lose its ability to reach outside the sandbox completely, until your app is restarted.
// Start accessing the file.
const stopAccessingSecurityScopedResource = app.startAccessingSecurityScopedResource(data)
// You can now access the file outside of the sandbox 🎉
// Remember to stop accessing the file once you've finished with it.
stopAccessingSecurityScopedResource()
Start accessing a security scoped resource. With this method Electron applications that are packaged for the Mac App Store may reach outside their sandbox to access files chosen by the user. See Apple's documentation for a description of how this system works.
app.enableSandbox()
Enables full sandbox mode on the app. This means that all renderers will be launched sandboxed, regardless of the value of the sandbox
flag in WebPreferences.
This method can only be called before app is ready.
app.isInApplicationsFolder()
macOS
Returns Boolean
- Whether the application is currently running from the
systems Application folder. Use in combination with app.moveToApplicationsFolder()
app.moveToApplicationsFolder([options])
macOS
options
Object (optional)conflictHandler
Function<Boolean> (optional) - A handler for potential conflict in move failure.conflictType
String - The type of move conflict encountered by the handler; can beexists
orexistsAndRunning
, whereexists
means that an app of the same name is present in the Applications directory andexistsAndRunning
means both that it exists and that it's presently running.
Returns Boolean
- Whether the move was successful. Please note that if
the move is successful, your application will quit and relaunch.
No confirmation dialog will be presented by default. If you wish to allow
the user to confirm the operation, you may do so using the
dialog
API.
NOTE: This method throws errors if anything other than the user causes the move to fail. For instance if the user cancels the authorization dialog, this method returns false. If we fail to perform the copy, then this method will throw an error. The message in the error should be informative and tell you exactly what went wrong.
By default, if an app of the same name as the one being moved exists in the Applications directory and is not running, the existing app will be trashed and the active app moved into its place. If it is running, the pre-existing running app will assume focus and the previously active app will quit itself. This behavior can be changed by providing the optional conflict handler, where the boolean returned by the handler determines whether or not the move conflict is resolved with default behavior. i.e. returning false
will ensure no further action is taken, returning true
will result in the default behavior and the method continuing.
For example:
app.moveToApplicationsFolder({
conflictHandler: (conflictType) => {
if (conflictType === 'exists') {
return dialog.showMessageBoxSync({
type: 'question',
buttons: ['Halt Move', 'Continue Move'],
defaultId: 0,
message: 'An app of this name already exists'
}) === 1
}
}
})
Would mean that if an app already exists in the user directory, if the user chooses to 'Continue Move' then the function would continue with its default behavior and the existing app will be trashed and the active app moved into its place.
app.isSecureKeyboardEntryEnabled()
macOS
Returns Boolean
- whether Secure Keyboard Entry
is enabled.
By default this API will return false
.
app.setSecureKeyboardEntryEnabled(enabled)
macOS
enabled
Boolean - Enable or disableSecure Keyboard Entry
Set the Secure Keyboard Entry
is enabled in your application.
By using this API, important information such as password and other sensitive information can be prevented from being intercepted by other processes.
See Apple's documentation for more details.
Note: Enable Secure Keyboard Entry
only when it is needed and disable it when it is no longer needed.
Properties
app.accessibilitySupportEnabled
macOS Windows
A Boolean
property that's true
if Chrome's accessibility support is enabled, false
otherwise. This property will be true
if the use of assistive technologies, such as screen readers, has been detected. Setting this property to true
manually enables Chrome's accessibility support, allowing developers to expose accessibility switch to users in application settings.
See Chromium's accessibility docs for more details. Disabled by default.
This API must be called after the ready
event is emitted.
Note: Rendering accessibility tree can significantly affect the performance of your app. It should not be enabled by default.
app.applicationMenu
A Menu | null
property that returns Menu
if one has been set and null
otherwise.
Users can pass a Menu to set this property.
app.badgeCount
Linux macOS
An Integer
property that returns the badge count for current app. Setting the count to 0
will hide the badge.
On macOS, setting this with any nonzero integer shows on the dock icon. On Linux, this property only works for Unity launcher.
Note: Unity launcher requires the existence of a .desktop
file to work,
for more information please read Desktop Environment Integration.
Note: On macOS, you need to ensure that your application has the permission to display notifications for this property to take effect.
app.commandLine
Readonly
A CommandLine
object that allows you to read and manipulate the
command line arguments that Chromium uses.
app.dock
macOS Readonly
A Dock
| undefined
object that allows you to perform actions on your app icon in the user's
dock on macOS.
app.isPackaged
Readonly
A Boolean
property that returns true
if the app is packaged, false
otherwise. For many apps, this property can be used to distinguish development and production environments.
app.name
A String
property that indicates the current application's name, which is the name in the application's package.json
file.
Usually the name
field of package.json
is a short lowercase name, according
to the npm modules spec. You should usually also specify a productName
field, which is your application's full capitalized name, and which will be
preferred over name
by Electron.
app.userAgentFallback
A String
which is the user agent string Electron will use as a global fallback.
This is the user agent that will be used when no user agent is set at the
webContents
or session
level. It is useful for ensuring that your entire
app has the same user agent. Set to a custom value as early as possible
in your app's initialization to ensure that your overridden value is used.
app.runningUnderRosettaTranslation
macOS Readonly
A Boolean
which when true
indicates that the app is currently running
under the Rosetta Translator Environment.
You can use this property to prompt users to download the arm64 version of your application when they are running the x64 version under Rosetta incorrectly.