建议使用JavaScript中的命名空间技术?表演者?要注意的问题? [英] Namespacing technique in JavaScript, recommended? performant? issues to be aware of?

问题描述

在项目中，我正在研究我正在构造我的代码如下

In a project I am working on I am structuring my code as follows

MyLib = {
    AField:0,

    ASubNamespace:{
        AnotherField:"value",

        AClass:function(param) {
            this.classField = param;

            this.classFunction = function(){
                // stuff
            }
        }
    },

    AnotherClass:function(param) {
        this.classField = param;

        this.classFunction = function(){
            // stuff
        }
    }
}

依此类推，例如:

var anInstance = new MyLib.ASubNamespace.AClass("A parameter.");

这是实现命名空间的正确方法吗?是否有性能方面的问题，如果有的话，有多大?当我嵌套得更深时，性能下降是否会叠加?使用此结构时，我还有其他需要注意的问题吗?

Is this the right way to go about achieving namespacing? Are there performance hits, and if so, how drastic? Do performance degradations stack as I nest deeper? Are there any other issues I should be aware of when using this structure?

我关心每一个性能，因为它是用于实时图形的库，所以我非常认真地考虑所有开销.

I care about every little bit of performance because it's a library for realtime graphics, so I'm taking any overhead very seriously.

推荐答案

在将代码构造为大型巨型对象属性层次结构时，有时会遇到MyNamespaceObj.prop1尚不适用于MyNamespaceObj.prop2的问题.还有一个事实，就是您经常在整个代码中多次键入完全限定的名称.

When you structure your code as a big giant object-property hierarchy, you sometimes have issues where MyNamespaceObj.prop1 isn't available to MyNamespaceObj.prop2 yet. And then there's the fact that you often end up typing fully qualified names a lot throughout the code.

我开始发现我更喜欢做这样的事情:

I'm starting to find I prefer doing something like this:

MyNamespaceObj = (function () {

    // lots of code/definitions that have local scope
    var internallyDefinedItem1 = function (n) { /* ... */ }
    var internallyDefinedItem2 = {
        foo: internallyDefinedItem1(532),
        bar: totallyPrivateNeverExportedFunction(17)
    }
    var totallyPrivateNeverExportedVar = 'blahblahblah';
    function totallyPrivateNeverExportedFunction (x) {
       /* ... */
    }

    return {
        exportedItem1: internallyDefinedItem1,
        exportedItem2: internallyDefinedItem2,
        ...
    }
})();

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