Array of peaks #2

[drzajwo]

Hi,
Sorry for "reopening" already closed issue. I'm implementing waveform to project I'm working on.
@Jchinonso In article you provided images/code gists for most important part for me are missing...

For now I'm using bbc/audiowaveform data and scale it like below:

  const clamp = (num, min, max) => {
    return num <= min ? min : num >= max ? max : num;
  };

  const scaleData = () => {
    // song can be 8 or 16 bits
    const max = Math.pow(2, bits - 1);
    const scaled = data.map((val, index) => {
      let scaledVal = val / max;
      // Not sure how to handle negative values...
      scaledVal = scaledVal < 0 ? scaledVal * -1 : scaledVal;
      return clamp(scaledVal, 0, 1);
    });
    return scaled;
  };

or filtering data from negative values

  const scaleData = () => {
    // song can be 8 or 16 bits
    const max = Math.pow(2, bits - 1);
    const scaled = data.filter((val) => val >= 0).map((val) => {
      let scaledVal = val / max;
      return clamp(scaledVal, 0, 1);
    });
    return scaled;
  };

Where data and bits are fetched from bbc data. This helps me to easily get values in rage [-1, 1] however you guys support values in range [0, 1] so in my code I'm converting negative values to positive (I'm pretty sure it's wrong :D ).