JavaScript:克隆一个功能 [英] JavaScript: clone a function
问题描述
想到两个选项: eval (func.toString())
和 function(){return func.apply(..)}
。但我担心eval的性能,并且包装会使堆叠变得更糟,并且如果应用了很多或应用于已包装,性能可能会降低性能。
新函数(args,body)
看起来不错,但是我可以如何可靠地将现有的函数拆分为args和body,而无需JS中的JS解析器?
在此先感谢。
更新:
我的意思是能够做到
var funcB = funcA.clone(); // clone()是我的扩展
funcB.newField = {...}; //不影响funcA
试试这个:
var x = function(){
return 1;
};
var t = function(a,b,c){
return a + b + c;
};
Function.prototype.clone = function(){
var that = this;
var temp = function temporary(){return that.apply(this,arguments); };
for(var key in this){
if(this.hasOwnProperty(key)){
temp [key] = this [key];
}
}
return temp;
};
alert(x === x.clone());
alert(x()=== x.clone()());
alert(t === t.clone());
alert(t(1,1,1)=== t.clone()(1,1,1));
alert(t.clone()(1,1,1));
What is a fastest way to clone a function in JavaScript (with or without its properties)?
Two options coming to mind are eval(func.toString())
and function() { return func.apply(..) }
. But I am worried about performance of eval and wrapping will make stack worse and will probably degrade performance if applied a lot or applied to already wrapped.
new Function(args, body)
looks nice, but how exactly can I reliable split existing function to args and body without a JS parser in JS?
Thanks in advance.
Update: What I mean is being able to do
var funcB = funcA.clone(); // where clone() is my extension
funcB.newField = {...}; // without affecting funcA
try this:
var x = function() {
return 1;
};
var t = function(a,b,c) {
return a+b+c;
};
Function.prototype.clone = function() {
var that = this;
var temp = function temporary() { return that.apply(this, arguments); };
for(var key in this) {
if (this.hasOwnProperty(key)) {
temp[key] = this[key];
}
}
return temp;
};
alert(x === x.clone());
alert(x() === x.clone()());
alert(t === t.clone());
alert(t(1,1,1) === t.clone()(1,1,1));
alert(t.clone()(1,1,1));
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