JS 时间格式转换

> 银行卡格式转换

```

// 每隔4个字符加空格间隔

const replaceStr = str => str.replace(/(\d{4})(?=\d)/g, '$1 ');

```

```

传入的参数格式为 yyyy-MM-dd hh:mm:ss 用正则替换后仅显示天数dd 代码如下

let s ="2019-07-13T15:58:53"; //yyyyMMddHHmmss

let  reg =/(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})/;

s = s.replace(reg, "$1年$2月$3日"); // yyyy/MM/dd HH:mm:ss

console.log(s) //2019年07月13日

{

let str ='2018-03-20';

    let reg =/(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;

    let {year, month, day} = str.match(reg).groups;

    console.log(year,month,day)//2018 03 20

}

{

let reg =/(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;

    let str ='2018-03-20';

    str.replace(reg, (...args)=>{

console.log(...args)

let {year, month, day} = args[args.length-1];

        console.log(year, month, day)

})

}

```