Silent sound generator hack for Safari audio permissions

hack.js

// James Cheese 2021 - based on example at https://developer.mozilla.org/en-US/docs/Web/API/AudioBufferSourceNode

// Build an audio context of whatever type's available
let SupportedAudioContext = null;
if (window.AudioContext !== undefined) {
    SupportedAudioContext = window.AudioContext;
} else if (window.webkitAudioContext !== undefined) {
    SupportedAudioContext = window.webkitAudioContext;
}
const silentAudioContext = new SupportedAudioContext();

// Create a buffer and ensure it's filled with zeroes (ie: silent)
const buffer = silentAudioContext.createBuffer(2, silentAudioContext.sampleRate * 3, silentAudioContext.sampleRate);
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
    const currentChannelBuffer = buffer.getChannelData(channel);
    for (var i = 0; i < buffer.length; i++) {
        currentChannelBuffer[i] = 0;
    }
}

// Hook the buffer up as a source for the audio context, and start streaming
const source = silentAudioContext.createBufferSource();
source.buffer = buffer;
source.loop = true;
source.connect(silentAudioContext.destination);
source.start();



// Might not be necessary for you - but poll to see if the audio context has started yet, then handle that state change
if (silentAudioContext.state !== "running") {
    // Poll to see if the audio context boots itself back up, mark as unmuted if that happens
    const interval = setInterval(() => {
        if (silentAudioContext.state === "suspended") {
            silentAudioContext.resume();
        }
        if (silentAudioContext.state === "running") {
            // We're unmuted - handle that however you need to

            clearInterval(interval); // But make sure to stop polling...
        }
    }, 500);
} else {
    // We're unmuted - handle that however you need to
}