code: function getDateData(date, month) {
  	const pos = getDatePos(date, month);
  
  	if (pos === null) {
  		throw new TypeError(JSON.stringify(date) + " is invalid format.");
  	}
  
  	return getDayData(pos.weekIndex, pos.weekDayIndex, month);
  }
docs: Gets specified date's info data in specified month.
  
  @param {object} date
  @param {object} month
  @throw {TypeError}
  @returns {Calendar~DateInfo}