Changing a set of values to a different ratio

change-to-new-ratio.js

function changeRatio(originalWidth, originalHeight, newWidth = 750, newHeight = 420, restrain = false) {
  let ratio = w / h,
      targetRatio = targetW / targetH;

  let newW = targetW,
      newH = newW / ratio;

  if (restrain && newH > targetH) {
    newH = targetH;
    newW = newH * ratio;
  }
  
  return {width: newW, height: newH}
}