SOURCE

// 测试数据如下：
// formatMoney(12.035); // 12.04 正常四舍五入
// formatMoney(12.045); // 12.04 异常，应该为12.05，没有四舍五入

// 解决如下
const formatMoney1 = (money, symbol = "", decimals = 2) => {
  let float = (
    Math.round((parseFloat(money) + Number.EPSILON) * Math.pow(10, decimals)) /
    Math.pow(10, decimals)
  ).toFixed(decimals);
  return `${symbol} ${float}`;
};
const method1 = formatMoney1(12.045)
console.log(method1)
/**
 * @params {Number} money 金额
 * @params {Number} decimals 保留小数点后位数
 * @params {String} symbol 前置符号
 */
const formatMoney2 = (money, symbol = "", decimals = 2) => {
  let result = money
    .toFixed(decimals)
    .replace(/\B(?=(\d{3})+\b)/g, ",")
    .replace(/^/, `${symbol}$ `);
  return result;
};

const method2 = formatMoney2(12.045, "$", 2); // $ 12,341,234.25
console.log(method2)

// 方式三：循环字符串，通过 slice 截取实现
// substring(start, end)：包含 start，不包含 end
// substr(start, length)：包含 start，长度为 length
// slice(start, end)：可操作数组和字符串；包含 start，不包含 end
// splice(start, length, items)：只能针对数组；增删改都可以

const formatMoney3 = (money, symbol = "", decimals = 2) => {
  let arr = money.toFixed(decimals).toString().split(".");
  let num = arr[0];
  let first = "";
  while (num.length > 3) {
    first = "," + num.slice(-3) + first;
    num = num.slice(0, num.length - 3);
  }
  if (num) {
    first = num + first;
  }
  return `${symbol} ${[first, arr[1]].join(".")}`;
};

const method3 = formatMoney3(12341234.045, "$", 2); // $ 12,341,234.25
console.log(method3)
// 链接：https://juejin.cn/post/7028086399601475591

// 方法4
let num= 12.046
console.log( num.toLocaleString("en-US") )
console.log((12341234.045).toFixed(2).toLocaleString())