mirror of https://github.com/electron/electron
60 lines
1.8 KiB
Markdown
60 lines
1.8 KiB
Markdown
# MessagePortMain
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`MessagePortMain` is the main-process-side equivalent of the DOM
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[`MessagePort`][] object. It behaves similarly to the DOM version, with the
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exception that it uses the Node.js `EventEmitter` event system, instead of the
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DOM `EventTarget` system. This means you should use `port.on('message', ...)`
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to listen for events, instead of `port.onmessage = ...` or
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`port.addEventListener('message', ...)`
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See the [Channel Messaging API][] documentation for more information on using
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channel messaging.
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`MessagePortMain` is an [EventEmitter][event-emitter].
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## Class: MessagePortMain
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> Port interface for channel messaging in the main process.
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Process: [Main](../glossary.md#main-process)<br />
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_This class is not exported from the `'electron'` module. It is only available as a return value of other methods in the Electron API._
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### Instance Methods
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#### `port.postMessage(message, [transfer])`
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* `message` any
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* `transfer` MessagePortMain[] (optional)
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Sends a message from the port, and optionally, transfers ownership of objects
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to other browsing contexts.
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#### `port.start()`
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Starts the sending of messages queued on the port. Messages will be queued
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until this method is called.
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#### `port.close()`
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Disconnects the port, so it is no longer active.
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### Instance Events
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#### Event: 'message'
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Returns:
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* `messageEvent` Object
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* `data` any
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* `ports` MessagePortMain[]
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Emitted when a MessagePortMain object receives a message.
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#### Event: 'close'
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Emitted when the remote end of a MessagePortMain object becomes disconnected.
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[`MessagePort`]: https://developer.mozilla.org/en-US/docs/Web/API/MessagePort
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[Channel Messaging API]: https://developer.mozilla.org/en-US/docs/Web/API/Channel_Messaging_API
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[event-emitter]: https://nodejs.org/api/events.html#events_class_eventemitter
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