Script for Audio Context Tutorial at my medium account (https://medium.com/@muhibbudins)

script.js

    // Prepare Canvas
    const context = canvas.getContext('2d');

    // Draw wave
    function draw() {
      requestAnimationFrame(draw);
      analyser.getByteFrequencyData(frequency);

      context.fillStyle = '#101010';
      context.fillRect(0, 0, canvas.width, canvas.height);

      context.lineWidth = 1.5;
      context.strokeStyle = colorize();
      context.beginPath();

      var sliceWidth = canvas.width * 1.0 / frequencyLength;
      var x = 0;

      for (var i = 0; i < frequencyLength; i++) {
        var v = frequency[i] / 256.0;
        var y = v * canvas.height / 2;

        if (i === 0) {
          context.moveTo(x, y);
        } else {
          context.lineTo(x, y);
        }

        x += sliceWidth;
      }

      context.lineTo(canvas.width, canvas.height / 2);
      context.stroke();
    };

    draw();