数字を3桁区切りに

これがベストプラクティスなんだろうか。

by FiNGAHOLiC

JavaScript

(function(){
    // http://sookibizviz.blog81.fc2.com/blog-entry-100.html
    // http://okadao.blogspot.jp/2009/10/javascript3.html
    function addFigure(str){
        var num = new String(str).replace(/,/g, "");
        while(num != (num = num.replace(/^(-?\d+)(\d{3})/, "$1,$2")));
        return num;
    };
    console.log(addFigure(3));
    console.log(addFigure(777));
    console.log(addFigure(5439843874749102));
    console.log(addFigure(-679998.765546));
}());