How to unlock Web Audio API audio on iOS devices with the ringer is off

main.js

import silenceDataURI from './silence-datauri';

// load a data url of short silence so that we can unlock web audio even when ringer is off
var audioTag = document.createElement("audio");
audioTag.controls = false;
audioTag.preload = "auto";
audioTag.loop = false;   // looping this seems to cause clicking on older iOS devices
audioTag.src = silenceDataURI;
document.addEventListener("visibilitychange", function() {
  if( document.visibilityState == 'visible' ) audioTag.play();
});

// call this just before you want to play Web Audio API audio, e.g., with SoundJS
// it should be called as part of a click/tap event handler
audioTag.play();

silence-datauri.js

export default "data:audio/mpeg;base64,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";