Javascript创建对象 - 多种方法，任何差异？ [英] Javascript creating objects - multiple approaches, any differences?

问题描述

我已经看到了一些在javascript中实例化对象的不同方法，想知道各种方法的优点/缺点以及为什么要使用其中一种方法。

I have seen a few different ways to instantiate objects in javascript, wanted to know the benefits/drawbacks of the various approaches and why you would use one over the other.

方法1

var obj = {
    prop: value,
    .
    .
    .
}

方法一是标准方法，没什么新东西：）

Approach one is standard approach, nothing new :)

方法2

var obj = new function() {
    var prop1 = value1;
    var fn1 = function() {
    };
    .
    .
    .

    this.prop2 = value2;
    .
    .
    .
}();

函数方法，我想将此方法与方法3进行比较。函数方法主要用于封装（正确吗？）

The function approach, I wanted to compare this approach with approach 3. The function approach is primarily used for encapsulation (correct?)

方法3

var obj = (function() {
    var prop1 = value1;
    var fn1 = function() {
    };
    .
    .
    .

    return {
        prop2: value2,
        .
        .
        .
    }
})();

通过这种方法，我不太清楚其使用背后的原因。它与方法2有何不同？两者都可以用来封装逻辑。

With this approach, I do not quite see the reasoning behind its usage. How does it differ from approach 2? Both can be used to encapsulate logic.

这样我们可以传递参数，所以我们可以处理任何潜在的冲突吗？例如jquery的 $ 语法 - 但您也可以使用方法2 ...

Is it so we can pass in parameters, so we can deal with any potential conflicts?? E.g jquery's $ syntax - but you can also do this with approach 2...

谢谢。

编辑：

我知道方法1和3是相似的（因为它们都返回对象）但是方法3也创建了一个闭包。哪种方法2也有。

I am aware the approach 1 and 3 are similar (in that they both return objects) however approach 3 also creates a closure. Which approach 2 also does.

这是我问题的基础，2和3都创建了闭包，但它们之间有什么区别。

That is the basis of my question really, both 2 and 3 create closures, but what is the difference between them.

推荐答案

在方法＃2和＃3中，结果对象的构造函数属性将不同。

In approaches #2 and #3 the constructor property of the resulting objects will be different.

实际上，这意味着第二种方法允许您使用匿名构造函数实例化多个对象：

In practice it means that the second approach allows you to instantiate more than one object using the anonymous constructor function:

x = new function() { alert(1) };
y = new x.constructor; // shows the message too

模块模式与匿名构造函数的实例包括道格拉斯克罗克福德的引用，其中他解释了为什么他认为方法＃3优于＃2。

The top answer to Module pattern vs. instance of an anonymous constructor includes a quote from Douglas Crockford in which he explains why he thinks the approach #3 is better than #2.

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