非常恼人的JavaScript数组/对象错误 [英] Extremely annoying JavaScript array/object error

问题描述

我的Web应用程序之一，我基本上是重写的部分。我有一个脚本，将立即崩溃的接口部分或全部的面板，另一个code它们。

Basically, I am rewriting part of one of my web applications. I had a script that would collapse some or all panels of the interface at once, and another to code them.

不过，我的老功能看起来很丑陋，烦人键入并不够强大：

However, my old functions looked really ugly, and were annoying to type and not powerful enough:

function collapse_all()
{
    document.getElementById("panel_1").style.display="none"
    document.getElementById("panel_2").style.display="none"
    document.getElementById("panel_3").style.display="none"
}
function expand_all()
{
    document.getElementById("panel_1").style.display=""
    document.getElementById("panel_2").style.display=""
    document.getElementById("panel_3").style.display=""
}

现在我有这样的：

function panel() //first variable in argument is collapse or expand, all others are panels to act on
{
    var panels = panel.arguments
    alert(typeof panel.arguments)
    var mode = panels.shift() //here's my problem
    if(mode=="collapse") {mode="none"}
    if(mode=="expand") {mode=""}
    var items = panels.length
    for (i = 0;i < items;i++) {document.getElementById(panels[i]).style.display=mode}
}

panel("collapse","panel_1","panel_2","panel_3")

我有一个问题，虽然。萤火告诉我panels.shift（）不是一个函数。一些谷歌搜索我设法找出panel.arguments不是一个数组而是一个对象，所以我不能用它阵列的方法。我真的很困惑，我怎么既可以将对象转换成一个数组或另寻解决办法，因为我知道旁边没有关​​于JavaScript对象。一些示例code将是非常美联社preciated。

I have a problem though. Firebug tells me panels.shift() is not a function. With some Googling I managed to find out that panel.arguments isn't an array but an object, so I can't use array methods on it. I'm just really confused as to how I could either convert the object into an array or find another workaround, as I know next to nothing about JavaScript objects. Some example code would be highly appreciated.

推荐答案

您可以将arguments对象到像这样的数组：

You can convert the arguments object into an array like this:

var argsArray = Array.prototype.slice.call(arguments);

这样做是通过 Array.prototype 使用片共同所有的阵列方法来创建一个真正的<从阵列状参数code>阵列对象。 （）调用（所有功能的方法）来调用这个片方法以的参数并没有参数此价值，它具有复制所有这个进入一个新的数组。这看似迂回或哈克，但它实际上是设计到语言：看到的注的 ECMAScript的第三版规范第15.4.4.10。

What this does is use the slice method common to all arrays via Array.prototype to create a genuine Array object from the array-like arguments. call() (a method of all functions) is used to call this slice method with a this value of arguments and no parameters, which has the effect of copying all of the elements of this into a new array. This may seem devious or hacky but it is actually designed into the language: see the note at the bottom of section 15.4.4.10 of the ECMAScript 3rd Edition spec.

此外，在函数中你所提供的参数对象作为一个变量，所以你并不需要访问它作为函数对象的属性，你是这样做。在你的情况，只需使用参数，而不是 panel.arguments 。

Also, within a function you are provided the arguments object as a variable, so you don't need to access it as a property of the function object as you are doing. In your case, just use arguments rather than panel.arguments.

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