数字千分位格式化

const numberToThousands = (num:string|number) => {

    num = (num || 0).toString()

    let result = '';

    while (num.length > 3) {

        result = ',' + num.slice(-3) + result;

        num = num.slice(0, num.length - 3);

    }

    if (num) {

      result = num + result;

    }

    return result;

  }