js函数钩子

设置函数调用前和调用后的两个钩子函数

Function.prototype.before = function (beforefn) {
  var __self = this;
    return function () {
        beforefn.apply(this, arguments);
        return __self.apply(this, arguments);
  };
};
Function.prototype.after = function (afterfn) {
  var __self = this;
  return function () {
      var ret = __self.apply(this, arguments);
      afterfn.apply(this, arguments);
      return ret;
  };
};
function greet () {
    console.log("hello")
}
greet.before(()=> {
    console.log("before")
}).after(()=> {
    console.log("after")
})()