files/en-us/web/api/audioworkletglobalscope/currentframe/index.md
{{APIRef("Web Audio API")}}
The read-only currentFrame property of the {{domxref("AudioWorkletGlobalScope")}} interface returns an integer that represents the ever-increasing current sample-frame of the audio block being processed. It is incremented by 128 (the size of a render quantum) after the processing of each audio block.
An integer number.
The {{domxref("AudioWorkletProcessor")}} has access to the specific {{domxref("AudioWorkletGlobalScope")}} properties:
// AudioWorkletProcessor defined in : test-processor.js
class TestProcessor extends AudioWorkletProcessor {
constructor() {
super();
// Logs the current sample-frame and time at the moment of instantiation.
// They are accessible from the AudioWorkletGlobalScope.
console.log(currentFrame);
console.log(currentTime);
}
// The process method is required - output silence,
// which the outputs are already filled with.
process(inputs, outputs, parameters) {
return true;
}
}
// Logs the sample rate, that is not going to change ever,
// because it's a read-only property of a BaseAudioContext
// and is set only during its instantiation.
console.log(sampleRate);
// You can declare any variables and use them in your processors
// for example it may be an ArrayBuffer with a wavetable.
const usefulVariable = 42;
console.log(usefulVariable);
registerProcessor("test-processor", TestProcessor);
The main script loads the processor, creates an instance of {{domxref("AudioWorkletNode")}}, passes the name of the processor to it, and connects the node to an audio graph. We should see the output of {{domxref("console/log_static", "console.log()")}} calls in the console:
const audioContext = new AudioContext();
await audioContext.audioWorklet.addModule("test-processor.js");
const testNode = new AudioWorkletNode(audioContext, "test-processor");
testNode.connect(audioContext.destination);
{{Specifications}}
{{Compat}}