将数字每千分位用逗号隔开

// 无小数版本
let format = n => {
    let num = n.toString() 
    let len = num.length
    if (len <= 3) {
        return num
    } else {
        return format(num.slice(0,len-3))+','+num.slice(len-3)
    }
}
let res=format(1232327666663)  // '1,232,323'
console.log(res)
1
2
3
4
5
6
7
8
9
10
11
12

// 有小数版本
let format = n => {
    let num = n.toString() // 转成字符串
    let decimals = ''
        // 判断是否有小数
    let index=num.indexOf('.') 
    if(index>-1)
    {
        decimals = num.slice(index)
        num=num.slice(0,index)
    }
    let len = num.length
    let res=''
    if (len <= 3) {
        res = num
    } else {
        res = format(num.slice(0,len-3))+','+num.slice(len-3)
    }
    return decimals?res+decimals:res
}
let res=format(123232.7666663)  // '1,232,323'
console.log(res)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23