Question

我正在尝试为对象中的每个函数添加一个钩子，以下是我的代码，它运行良好。

    function foo(){}
    foo.beforeMethodHook = function(){console.log('Hook was called.');}
    foo.getInstance = function(){
        var newInstance = new foo;
        var funcNames = Object.getOwnPropertyNames(foo);
        for(i in funcNames){
            var funcName = funcNames[i];
            if(funcName == 'getInstance' || funcName == 'beforeMethodHook' || Object.hasOwnProperty(funcName)) continue;
            newInstance[funcName] = function (){
                foo.beforeMethodHook();
                return foo[this].apply(foo,arguments);
            }.bind(funcName);
        }
        return newInstance;
    }
    foo.test1 = function(arg1){console.log('test1 was called. arg1 = ' + arg1);return true;}
    foo.test2 = function(arg1,arg2){console.log('test2 was called. arg1 = ' + arg1 + ' , arg2 = ' + arg2);return true;}
    //Test
    var f = foo.getInstance();
    f.test1('ahaha');
    f.test2('heihei','houhou');

由于IE10-不支持function（）{}。bind（），我试图将.bind（）更改为（function（）{}）（），后面跟着

    newInstance[funcName] = (function (){
        foo.beforeMethodHook();console.log(arguments);
        return foo[funcName].apply(foo,arguments);
    })(funcName);

但问题来了，我失去了论证 f.test1（'ahaha'）已经过去了。 arguments数组只给出[“test1”]这是函数名。

我该如何解决？提前谢谢。

Answer 1

您可以实施自己的bind。简易版：

if (!Function.prototype.bind) {
    Function.prototype.bind = function(that) {
        var fn = this;
        return function() {
            fn.apply(that, arguments);
        }
    };
}

或正确的版本：

if (!Function.prototype.bind) {
  Function.prototype.bind = function (oThis) {
    if (typeof this !== "function") {
      // closest thing possible to the ECMAScript 5 internal IsCallable function
      throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");
    }

    var aArgs = Array.prototype.slice.call(arguments, 1), 
        fToBind = this, 
        fNOP = function () {},
        fBound = function () {
          return fToBind.apply(this instanceof fNOP && oThis
                                 ? this
                                 : oThis,
                               aArgs.concat(Array.prototype.slice.call(arguments)));
        };

    fNOP.prototype = this.prototype;
    fBound.prototype = new fNOP();

    return fBound;
  };
}

代码取自：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Answer 2

尝试使用此处提供的bind的替代代码

<强> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind?redirectlocale=en-US&redirectslug=JavaScript%2FReference%2FGlobal_Objects%2FFunction%2Fbind

Answer 3

你应该做这样的事情

 newInstance[funcName] = (function (){
        console.log(arguments);
        return function(){
          foo.beforeMethodHook();
          foo[funcName].apply(foo,arguments);
        }
    })(funcName);

在JavaScript中使用（）（）将参数传递给匿名函数

3 个答案: