convertValueToPx = ($el, v, size, under, over) => {
  const clampMin = v === 'min';
  const clampMax = v === 'max';
  const value = v === 'top' || v === 'left' || v === 'start' || clampMin ? 0 :
                v === 'bottom' || v === 'right' || v === 'end' || clampMax ? '100%' :
                v === 'center' ? '50%' :
                v;
  const { n, u } = decomposeRawValue(value, decomposedOriginalValue);
  let px = n;
  if (u === '%') {
    px = (n / 100) * size;
  } else if (u) {
    px = convertValueUnit($el, decomposedOriginalValue, 'px', true).n;
  }
  if (clampMax && under < 0) px += under;
  if (clampMin && over > 0) px += over;
  return px;
}
@param {HTMLElement} $el
@param {Number|string} v
@param {Number} size
@param {Number} [under]
@param {Number} [over]
@return {Number}