const { createAudioBars, updateAudioBars } = require('audio-frequency-tempered');

// create audio context, analyser, data array
// omitted: source, gain, connect, etc.
const audioCtx = new AudioContext();
const analyser = audioCtx.createAnalyser();
const audioData = new Uint8Array(analyser.frequencyBinCount);

// create audio bars
const audioBars = createAudioBars({ groupLevel: 8 });

// on update
analyser.getByteFrequencyData(audioData);
updateAudioBars(audioData);

audioBars.forEach(bar => console.log(bar));

{ value: 0.6078, factor: 1, iniBin: 6, endBin: 9 }
{ value: 0.8196, factor: 1, iniBin: 10, endBin: 18 }
{ value: 0.8980, factor: 1, iniBin: 19, endBin: 37 }
{ value: 0.7254, factor: 1, iniBin: 38, endBin: 73 }
{ value: 0.5215, factor: 1, iniBin: 74, endBin: 146 }
{ value: 0.4352, factor: 1, iniBin: 147, endBin: 292 }
{ value: 0.4627, factor: 1, iniBin: 293, endBin: 584 }
{ value: 0.4313, factor: 1, iniBin: 585, endBin: 1167 }
{ value: 0.3411, factor: 1, iniBin: 1168, endBin: 2333 }
{ value: 0.0000, factor: 1, iniBin: 2334, endBin: 3110 }