JavaScript:克隆一个函数 [英] JavaScript: clone a function
问题描述
在 JavaScript 中克隆一个函数的最快方法是什么(有或没有它的属性)?
What is a fastest way to clone a function in JavaScript (with or without its properties)?
想到的两个选项是 eval(func.toString())
和 function() { return func.apply(..) }
.但我担心 eval 和 wrapping 的性能会使堆栈变得更糟,如果大量应用或应用于已经包装的,可能会降低性能.
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)
看起来不错,但是在 JS 中没有 JS 解析器的情况下,我如何可靠地将现有函数拆分为 args 和 body?
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?
提前致谢.
更新:我的意思是能够做到
var funcB = funcA.clone(); // where clone() is my extension
funcB.newField = {...}; // without affecting funcA
推荐答案
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));
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