javascript(js)按照指定長度為 數字/字串 前面補零(補0)

資料來源: https://blog.csdn.net/qq_41854291/article/details/115344291

code01

function pad(num, n) {
    var i = (num + "").length;
    while(i++ < n) num = "0" + num;
    return num;
}

code02

function PrefixInteger(num, length) {
    return (num/Math.pow(10,length)).toFixed(length).substr(2);
}

code03

function PrefixInteger(num, length) {
    return ( "0000000000000000" + num ).substr( -length );
}

code04[高效+簡潔] ~ 選用 & 測試 -> OK

function PrefixInteger(num, length) {
    return (Array(length).join('0') + num).slice(-length);
}

code05[遞迴]

function pad2(num, n) {
    if ((num + "").length >= n)
        return num;
    return pad2("0" + num, n);
}