function toTransformString(x, y, scale) {
  let propValue = `translate3d(${x}px,${y || 0}px,0)`;

  if (scale !== undefined) {
    propValue += ` scale3d(${scale},${scale},1)`;
  }

  return propValue;
}
Get transform string

@param {number} x
@param {number} [y]
@param {number} [scale]
@returns {string}