'use strict';
  
  var getMonth = Date.prototype.getMonth;
  
  module.exports = function () {
  	switch (getMonth.call(this)) {
  	case 1:
  		return this.getFullYear() % 4 ? 28 : 29;
  	case 3:
  	case 5:
  	case 8:
  	case 10:
  		return 30;
  	default:
  		return 31;
  	}
  };