Convert an argument representing a datetime into a Date object.

convert_to_date_object.js

/**
 * Converts an argument representing a datetime into a Date object.
 *
 * @param {string|number|Date} time Argument representing a datetime.
 *
 * @return {Date} The Date object representing the specified datetime.
 */
function convert_to_date_object(time)
{
  switch (typeof time) {
    case 'number':
      break;
    case 'string':
      time = + new Date(time);
      break;
    case 'object':
      if (time.constructor === Date) {
        time = time.getTime();
      }
      break;
    default:
      time = + new Date();
  }
  return time;
}