vue过滤器中使用 

filters: {
    //第一种
    Statistic(num) {
      let [integer, decimal] = String.prototype.split.call(num, '.')
      integer = (integer || 0).toString()
      let result = ''
      while (integer.length > 3) {
        result = ',' + integer.slice(-3) + result
        integer = integer.slice(0, integer.length - 3)
      }
      if (integer) {
        result = integer + result
      }
      return `${result}${decimal ? '.' + decimal : ''}`
    },
    //第二种
    Statistic1(num) {
      num = parseFloat(Number(num).toFixed(3))
      let [integer, decimal] = String.prototype.split.call(num, '.')
      integer = integer.replace(/\d(?=(\d{3})+$)/g, '$&,') // 正则先行断言
      return `${integer}${decimal ? '.' + decimal : ''}`
    },
    //第三种
    let thousandth = (s, type = 0) => {
      // if (!s) return '0';
      // return (s+'').replace(/(\d{1,3})(?=(\d{3})+(?:$|\.))/g,'$1,');

      if (/[^0-9\.]/.test(s)) return "0";
      if (s == null || s == "") return "0";
      s = s.toString().replace(/^(\d*)$/, "$1.");
      s = (s + "00").replace(/(\d*\.\d\d)\d*/, "$1");
      s = s.replace(".", ",");
      var re = /(\d)(\d{3},)/;
      while (re.test(s)) s = s.replace(re, "$1,$2");
      s = s.replace(/,(\d\d)$/, ".$1");
      if (type == 0) {
        // 不带小数位(默认是有小数位)
        var a = s.split(".");
        if (a[1] == "00") {
          s = a[0];
        }
      }
      return s;
    }
}

js函数

第一种
function toThousands(num) {
  let [integer, decimal] = String.prototype.split.call(num, '.')
  integer = (integer || 0).toString()
  let result = ''
  while (integer.length > 3) {
  result = ',' + integer.slice(-3) + result
  integer = integer.slice(0, integer.length - 3)
  }
  if (integer) {
  result = integer + result
  }
  return `${result}${decimal ? '.' + decimal : ''}`
},
第二种
function toThousands(num) {
  num = parseFloat(Number(num).toFixed(3))
  let [integer, decimal] = String.prototype.split.call(num, '.')
  integer = integer.replace(/\d(?=(\d{3})+$)/g, '$&,') // 正则先行断言
  return `${integer}${decimal ? '.' + decimal : ''}`
},

注意

num.toFixed is not a function(js报错)
toFixed 是Number类型的方法 所以要改为 num = Number(num).toFixed(2);