MessagePort

The MessagePort interface of the Channel Messaging API represents one of the two ports of a MessageChannel, allowing messages to be sent from one port and listening out for them arriving at the other.

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Extends

• EventTarget.MessageEventTarget<MessagePort>

Methods

addEventListener()

Call Signature

addEventListener<K>(
   type, 
   listener, 
   options?
): void;

The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target.

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Type Parameters

Type Parameter
K extends keyof MessagePortEventMap

Parameters

Parameter	Type
type	K
listener	(this, ev) => any
options?	boolean | AddEventListenerOptions

Returns

void

Overrides

EventTarget.addEventListener

Call Signature

addEventListener(
   type, 
   listener, 
   options?
): void;

The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target.

MDN Reference

Parameters

Parameter	Type
type	string
listener	EventListenerOrEventListenerObject
options?	boolean | AddEventListenerOptions

Returns

void

Overrides

MessageEventTarget.addEventListener

---

close()

close(): void;

The close() method of the MessagePort interface disconnects the port, so it is no longer active. This stops the flow of messages to that port.

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Returns

void

---

dispatchEvent()

dispatchEvent(event): boolean;

The dispatchEvent() method of the EventTarget sends an Event to the object, (synchronously) invoking the affected event listeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) also apply to events dispatched manually with dispatchEvent().

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Parameters

Parameter	Type
event	Event

Returns

boolean

Inherited from

EventTarget.dispatchEvent

---

postMessage()

Call Signature

postMessage(message, transfer): void;

The postMessage() method of the MessagePort interface sends a message from the port, and optionally, transfers ownership of objects to other browsing contexts.

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Parameters

Parameter	Type
message	any
transfer	Transferable[]

Returns

void

Call Signature

postMessage(message, options?): void;

Parameters

Parameter	Type
message	any
options?	StructuredSerializeOptions

Returns

void

---

removeEventListener()

Call Signature

removeEventListener<K>(
   type, 
   listener, 
   options?
): void;

The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget.addEventListener() from the target. The event listener to be removed is identified using a combination of the event type, the event listener function itself, and various optional options that may affect the matching process; see Matching event listeners for removal.

MDN Reference

Type Parameters

Type Parameter
K extends keyof MessagePortEventMap

Parameters

Parameter	Type
type	K
listener	(this, ev) => any
options?	boolean | EventListenerOptions

Returns

void

Overrides

EventTarget.removeEventListener

Call Signature

removeEventListener(
   type, 
   listener, 
   options?
): void;

The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget.addEventListener() from the target. The event listener to be removed is identified using a combination of the event type, the event listener function itself, and various optional options that may affect the matching process; see Matching event listeners for removal.

MDN Reference

Parameters

Parameter	Type
type	string
listener	EventListenerOrEventListenerObject
options?	boolean | EventListenerOptions

Returns

void

Overrides

MessageEventTarget.removeEventListener

---

start()

start(): void;

The start() method of the MessagePort interface starts the sending of messages queued on the port. This method is only needed when using EventTarget.addEventListener; it is implied when using onmessage.

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Returns

void

Properties

onmessage

onmessage: ((this, ev) => any) | null;

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Inherited from

MessageEventTarget.onmessage

---

onmessageerror

onmessageerror: ((this, ev) => any) | null;

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Inherited from

MessageEventTarget.onmessageerror