AudioWorkletNode: port property
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The read-only port property of the
AudioWorkletNode interface returns the associated
MessagePort. It can be used to communicate between the node and its
associated AudioWorkletProcessor.
Note:
The port at the other end of the channel is
available under the port property of the
processor.
Value
The MessagePort object that is connecting the
AudioWorkletNode and its associated AudioWorkletProcessor.
Examples
To demonstrate bidirectional communication capabilities, we'll create an
AudioWorkletProcessor, which will output silence and respond to ping
requests from its AudioWorkletNode.
First, we need to define a custom AudioWorkletProcessor, and register it.
Note that this should be done in a separate file.
// ping-pong-processor.js
class PingPongProcessor extends AudioWorkletProcessor {
constructor(...args) {
super(...args);
this.port.onmessage = (e) => {
console.log(e.data);
this.port.postMessage("pong");
};
}
process(inputs, outputs, parameters) {
return true;
}
}
registerProcessor("ping-pong-processor", PingPongProcessor);
Now in our main scripts file we'll load the processor, create an instance of
AudioWorkletNode passing the name of the processor, and connect the node to
an audio graph.
const audioContext = new AudioContext();
await audioContext.audioWorklet.addModule("ping-pong-processor.js");
const pingPongNode = new AudioWorkletNode(audioContext, "ping-pong-processor");
// send the message containing 'ping' string
// to the AudioWorkletProcessor from the AudioWorkletNode every second
setInterval(() => pingPongNode.port.postMessage("ping"), 1000);
pingPongNode.port.onmessage = (e) => console.log(e.data);
pingPongNode.connect(audioContext.destination);
This will output "ping" and "pong" strings to the console
every second.
Specifications
| Specification |
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| Web Audio API # dom-audioworkletnode-port |
Browser compatibility
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Legend
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- Full support
- Full support