原来:2021-2-21 2:9:0

要实现的效果:2021-02-21 02:09:00

    const date = new Date()
const today
= date.getFullYear()+'-'+('0'+(date.getMonth()+1).toString()).slice(-2)+'-'+date.getDate()+' '+('0'+date.getHours()).slice(-2)+':'+('0'+date.getMinutes()).slice(-2)+':'+('0'+date.getSeconds()).slice(-2)
console.log(today) //
2021-02-21 14:28:46

要点 : 前面➕字符串 0 , 再使用字符串的 slice 方法始终截取两位.