JavaScript 对象属性查找 - 语法重要吗？

发布于 2024-11-13 01:10:15 字数 546 浏览 4 评论 0原文

这是一个关于 JavaScript (ECMAScript) 语言的基本问题，所以如果它是重复的，我提前道歉（一点搜索没有揭示我的确切问题）。

在 ECMAScript 中，我们可以使用两种基本语法形式来获取/设置对象的属性，并且它们似乎具有完全相同的效果。由于我不太了解，我将它们称为“属性”和“关联数组”符号：

var o = {};
// Property notation.
o.foo = 'Foo'; // (set)
o.foo; // => "Foo" (get)
// Associative array notation.
o['bar'] = 'Bar'; // (set)
o['bar']; // => "Bar" (get)
// They seem to be interchangeable.
o['foo']; // => "Foo"
o.bar; // => "Bar"

这两种符号之间有什么真正的区别吗？显然，关联数组表示法允许我们查找对象上动态生成的键（并强制将其参数强制转换为字符串），而属性表示法使用文字，但这是唯一的区别吗？

原文

This is a basic question about the JavaScript (ECMAScript) language so I apologize in advance if it's a duplicate (a little searching didn't reveal my exact question).

In ECMAScript we can use two basic syntactic forms to get/set properties on an object and they seem to have the exact same effect. Since I don't know better, I'll call them "property" and "associative array" notations:

var o = {};
// Property notation.
o.foo = 'Foo'; // (set)
o.foo; // => "Foo" (get)
// Associative array notation.
o['bar'] = 'Bar'; // (set)
o['bar']; // => "Bar" (get)
// They seem to be interchangeable.
o['foo']; // => "Foo"
o.bar; // => "Bar"

Are there any real differences between these two notations? Obviously, the associative array notation allows us to lookup dynamically generated keys on the object (and forcibly casts its argument to a string) whereas the property notation uses a literal but is that the only difference?

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