async play() { let upload = document.getElementById("file1"); let f = upload.files[0]; var ctx = new AudioContext(); var source = ctx.createBufferSource(); var data = f.slice(0); let v = await data.arrayBuffer(); console.log(v); ctx.decodeAudioData(v).then(function (decodeData) { source.buffer = decodeData; source.connect(ctx.destination); source.start(0); });