Example code:
if (strNum.length <= 3) {
return strNum;
}
if (!/^( |-)?(d )(.d )?$/.test(strNum)) {
return strNum;
}
var a = RegExp.$1, b = RegExp.$2, c = RegExp.$3;
var re = new RegExp();
re.compile("(\d)(\d{3})(,|$)");
while (re.test(b)) {
b = b.replace(re, "$1,$2$3");
}
return a "" b "" c;
}
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
