JS時間格式轉成字符串

formatNumber = n => {
      n = n.toString();
      return n[1] ? n : '0' + n
    };
    // 時間格式化
formatTime = date => {
       const year = date.getFullYear();
       const month = date.getMonth() + 1;
        const day = date.getDate();
        const hour = date.getHours()
        const minute = date.getMinutes()
        const second = date.getSeconds()
        return [year, month, day].map(formatNumber).join('-') + ' ' + [hour, minute, second].map(formatNumber).join(':')
   };

使用方法：

　　let date = new Date("2020-6-8")

　　let newDate = formatTime(date)  //  or formatTime(new Date())

　　console.log(newDate， "==============")

　　// 2020-06-08 ===============