js格式化金额 每三位,分隔开

_formatMoney=(nStr)=> {
        nStr += '';
        let x = nStr.split('.');
        let x1 = x[0];
        let x2 = x.length > 1 ? '.' + x[1] : '';
        let rgx = /(\d+)(\d{3})/;
        while (rgx.test(x1)) {
            x1 = x1.replace(rgx, '$1' + ',' + '$2');
        }
        return x1 + x2;
    }