function around(obj, prop, advice){ var exist = obj[prop]; var previous = function(){ return exist.apply(obj, arguments); }; var advised = advice(previous); obj[prop] = function(){ //当调用remove后，advised为空 //利用闭包的作用域链中可以访问到advised跟previous变量，根据advised是否为空可以来决定调用谁 return advised ? advised.apply(obj, arguments) : previous.apply(obj, arguments); }; return { remove: function(){ //利用闭包的作用域链，在remove时将advised置空，这样执行过程中不会进入本次around //这几个不能删 //obj[prop] = exist; advised = null; advice = null; //previous = null; //exist = null; //obj = null; } } } var count = 1; advice = function(originalFunc){ var current = count++; return function() { console.log("before function " + current); originalFunc.apply(this, arguments); console.log("after function " + current); } } var obj = { foo: function(arg){ console.log(this.name + " and " + arg); }, name: "obj" } h1 = around(obj, 'foo', advice); h2 = around(obj, 'foo', advice); obj.foo('hello world'); h1.remove(); obj.foo('hello world'); h2.remove(); obj.foo('hello world');
输出：
before function 2 before function 1 obj and hello world after function 1 after function 2 before function 2 obj and hello world after function 2 obj and hello world
打完，收功！
第一次通宵写博客也是醉了，两点钟听到隔壁fuck me，四点钟听到乌鸦啼鸣，还有一种不知道什么鸟，啾啾的叫，五点钟这个时候一堆鸟叫。。。。
参考文章：
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