if (!String.prototype.padStart) {
  String.prototype.padStart = function padStart(targetLength, padString) {
    targetLength = targetLength >> 0;
    padString = String(typeof padString !== 'undefined' ? padString : ' ');
    if (this.length > targetLength) {
      return String(this);
    } else {
      targetLength = targetLength - this.length;
      if (targetLength > padString.length) {
        padString += padString.repeat(targetLength / padString.length); //append to original to ensure we are longer than needed
      }
      return padString.slice(0, targetLength) + String(this);
    }
  };
}