날짜 포맷

dateFormat : function(date) {
	let dt = new Date(date);
	let yyyy = dt.getFullYear();
	let mm = String(dt.getMonth() + 1);
	let dd = String(dt.getDate());

	return String(yyyy) +'-'+ String(mm[1]?mm:'0'+mm[0])+'-'+String(dd[1]?dd:'0'+dd[0]);
}