-----------------组件||插件------------------

export default {
  install(Vue) {     // 重点--->install
    Vue.prototype.$formatMoney = function(s, n) {
      n = n >= 0 && n <= 20 ? n : 2;
      s = parseFloat((s + '').replace(/[^\d\.-]/g, '')).toFixed(n) + '';
      var l = s.split('.')[0].split('').reverse(); var r = s.split('.')[1];
      r = r == null ? '' : '.' + r;
      var t = '';
      //   console.log(l)
      if (l[l.length - 1] === '-') {
        // 负数不需要分隔号,

        for (var i = 0; i < l.length; i++) {
          if (l[i] === '-') {
            t += l[i] + ''
            continue
          }
          // 不是数组的倒数第二个元素才加"," ["0", "4", "5", "-"]
          t += l[i] + ((i + 1) % 3 == 0 && i + 1 != l.length - 1 ? ',' : '')
          // i + 1 != l.length会变成-,540.00,因为在5时元素位置2+1为3非数组长度
          // t += l[i] + ((i + 1) % 3 == 0 && i + 1 != l.length ? "," : "");
        }
      } else {
        for (var i = 0; i < l.length; i++) {
          t += l[i] + ((i + 1) % 3 == 0 && i + 1 != l.length ? ',' : '');
        }
      }
      return (
        t.split('').reverse().join('') + r
      )
    }
  }
}

----------------------main.js||main.ts----------------------------

import formatMoney from './components/common/formatMoney'
Vue.use(formatMoney)