AudioContext: outputLatency property

The outputLatency read-only property of the AudioContext Interface provides an estimation of the output latency of the current audio context.

This is the time, in seconds, between the browser passing an audio buffer out of an audio graph over to the host system's audio subsystem to play, and the time at which the first sample in the buffer is actually processed by the audio output device.

It varies depending on the platform and the available hardware.

const audioCtx = new AudioContext();
console.log(audioCtx.outputLatency);