Javascript对象构造函数与对象文字 [英] Javascript object constructor vs object literal

问题描述

可能重复：

创建对象 - 新对象或对象文字符号？

文字符号VS.用JavaScript创建对象的构造函数

我正在通过我的第一个Javascript教程。

I'm going through my very first Javascript tutorial.

我刚刚发现了两种创建JS对象的方法。

I just found two ways to create a JS object.

var person = new Object();
person.name = "Tom";
person.age = "17";

和

var person = {};
person.name = "Tom";
person.name = "17"

这两种对象创建方式有何不同？由于第二个看起来更简单，我们是否可以在任何条件下使用它？

Any difference between these two ways of object creation? Since the second looks simpler, can we always use it under any condition?

推荐答案

第二种语法不仅更易于阅读，而且不仅可以在任何条件下工作，而且第一种语法可能不会在所有条件下工作：

Not only is the second syntax easier to read and not only will it work under any condition, but the first syntax might not work under all conditions:

function Object() {
    // Oh crap, we have redefined Object!
    return [];    // return an array because we are EVIL
}

var person = new Object();   // not what we think it is

但是 {} ，作为一个句法结构，不受这种邪恶的诡计的影响。

But {}, being a syntactic construct, is immune to such evil trickery.

此外，对象文字符号可以在分析时部分优化，因为毕竟有只能创建一种对象类型。这可能会导致性能上升微不足道。

In addition, the object literal notation can be partially optimized at parse time, since after all there's only one object type that could be created. That may result in a minuscule performance increase.

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