code: function toTimestamp(date) {
      var value =
          (typeof date === 'number') ? date :           // number
          (date instanceof Date)     ? date.valueOf() : // Date
          new Date(date).valueOf();                     // ISOString, momentjs, ...
  
      if (isNaN(value)) {
        throw new TypeError('Invalid date ' + JSON.stringify(date) + '. ' +
            'Date, number, or ISOString expected');
      }
  
      return value;
    }
docs: Convert a Date, number, or ISOString to a number timestamp,
  and validate whether it's a valid Date. The number Infinity is also
  accepted as a valid timestamp
  @param {Date | number | string} date
  @return {number} Returns a unix timestamp, a number