字符串数据处理方式

1.手机号隐藏中间4位

代码：

      let str = 15945253565;
  var reg = /^(\d{3})\d{4}(\d{4})$/;
       let a = str.replace(reg, "$1****$2");
       console.log(a) 

2.数字3位数隔开

                let wordCount = 130320;
                var str = wordCount.toString();
                var reg = str.indexOf(".") > -1 ? /(\d)(?=(\d{3})+\.)/g : /(\d)(?=(?:\d{3})+$)/g;
                str = str.replace(reg, "$1,");