我想用一个调用原始版本的新版本覆盖Javascript内置函数(类似于在一个类上覆盖一个方法,其版本调用 super 在许多语言中)。我该怎么做?
I would like to override a Javascript built-in function with a new version that calls the original (similarly to overriding a method on a class with a version that calls super in many languages). How can I do this?
例如......
window.alert = function(str) { //do something additional if(console) console.log(str); //super.alert(str) // How do I do this bit? }推荐答案
存储对原始文件的引用变量中的函数:
Store a reference to the original function in a variable:
(function() { var _alert = window.alert; // <-- Reference window.alert = function(str) { // do something additional if(console) console.log(str); //return _alert.apply(this, arguments); // <-- The universal method _alert(str); // Suits for this case }; })();通用方法是 < original_func_reference> .apply(this,arguments) - 保留上下文并传递所有论点。通常,也应该返回原始方法的返回值。
The universal way is <original_func_reference>.apply(this, arguments) - To preserve context and pass all arguments. Usually, the return value of the original method should also be returned.
但是,已知 alert 是一个void函数,只接受一个参数,并且不使用这个对象。因此,在这种情况下, _alert(str)就足够了。
However, it's known that alert is a void function, takes only one argument, and does not use the this object. So, _alert(str) is sufficient in this case.
注意:IE< = 8会引发错误如果你试图覆盖 alert ,那么请确保你使用的是 window.alert = ... 而不是 alert = ... 。
Note: IE <= 8 throws an error if you try to overwrite alert, so make sure that you're using window.alert = ... instead of alert = ....
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覆盖功能(例如“警报”)并调用原始功能?
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