题解 | #分隔符#

function _comma(number) {
    let flag = 0;
    if (number < 0) {
        flag = 1
        number = -number
    }

    let a = number.toString().split('').reverse();
    let s = new Array();
    for (let i = 0; i < a.length; i++) {
        if (i % 3 == 0 && i != 0) {
            s.push(',')
        }
        s.push(a[i])
    }
    if (flag == 1) {
        return '-' + s.reverse().join('')
    }
    return s.reverse().join('')
}