How to convert a number from one range to another

const scaleValue = (value, from, to) => {
  const scale = (to[1] - to[0]) / (from[1] - from[0])
  const capped = Math.min(from[1], Math.max(from[0], value)) - from[0]
  return capped * scale + to[0]
}

export default scaleValue

const v = scaleValue(20, [0,100], [0, 400])
// 80