javaScript保留关键字 [英] javaScript reserved keywords

问题描述

我想知道如何管理JavaScript的保留关键字/功能。

I am wondering how JavaScript's reserved keywords / functions are managed.

示例：

根据：

http://www.quackit.com/javascript/javascript_reserved_words.cfm

delete 是JavaScript提供的保留关键字。

delete is a reserved keyword by JavaScript.

然后考虑以下代码片段：

Then consider the following snippet for some context:

var cookieManager = {
    get: function (name) { 
        // function contents ...
        console.log("cookieManager.get() called");
        return true;
    },
    set: function (name, value, days) {
        // function contents ...
        console.log("cookieManager.set() called");
        return true;
    },
    delete: function (name) { 
        // function contents ...
        console.log("cookieManager.delete() called");
        return true;
    }
};

此对象有一个 delete 属性它的名称是由JavaScript保留的，所以它应该失败，对吧？

This object has a delete property, yet the name of it is reserved by JavaScript so it should fail, right?

然而当我执行时，cookieManager.delete（）; 在 webconsole 的 FireFox 我得到以下输出，表明它工作正常：

Yet when I execute cookieManager.delete(); in the webconsole of FireFox I get the following output, suggesting that it works fine:

[11:26:00.654] cookieManager.delete();
[11:26:00.656] cookieManager.delete() called
[11:26:00.657] true

但是，如果您在 JsLint 中运行代码，则表示

If, however, you run the code in JsLint it says

Problem at line 12 character 5: Expected an identifier and instead saw 'delete' (a reserved word).

delete: function (name) { 

建议这是一个很大的没有没有方法，应该避免。

Suggesting that this is a big no no approach and should be avoided.

所以我什么时候应该考虑保留关键字，就像在这个例子中它似乎工作就像我希望它（delete关键字在对象cookieManager的上下文中，因此不会导致冲突，因此可以使用）或者我应该遵守 JsLint 并通过javascript重命名任何保留关键字？在这种情况下，我可以轻松地将.delete（）重命名为.remove（）。

So when should I take reserved keywords into consideration, as in this example it seems to work just like I want it to ( the delete keyword is in the context of the object cookieManager and thus causes no conflicts, hence it can be used ) or should I abide to the bible that is JsLint and rename anything that is a reserved keyword by javascript? In this context I could easily rename .delete() to .remove().

推荐答案

实际上这是允许的，因为 ECMAScript规范。对象文字的制作规则（第11.1.5节）是：

Actually this is allowed as per ECMAScript specification. The production rules (Section 11.1.5) for an object literal are:

ObjectLiteral :
    {}
    {PropertyNameAndValueList}
    {PropertyNameAndValueList  ,}

PropertyNameAndValueList :
    PropertyAssignment
    PropertyNameAndValueList , PropertyAssignment

PropertyAssignment :
    PropertyName : AssignmentExpression
    get PropertyName ( ){FunctionBody}
    set PropertyName (PropertySetParameterList){FunctionBody}

PropertyName :
    IdentifierName
    StringLiteral
    NumericLiteral

在您的情况下，您使用 IdentifierName 作为属性名称。 第7.6.1节说：

In your case, you use an IdentifierName as property name. Section 7.6.1 says:

保留字是 IdentifierName ，不能用作标识符 。

注意区别：您不能将保留关键字用作标识符，但因为它是有效的 IdentifierName 您可以将其用作 PropertyName 。

Note the difference: You cannot use a reserved keyword as Identifier, but as it is a valid IdentifierName you can use it as PropertyName.

尽管如此，其他（版本）浏览器可能不会容忍这一点，所以为了安全起见，我会重命名它。

Nevertheless, other (versions of) browsers might not tolerate this, so to be on the safe side, I would rename it.

除了浏览器可能出现的问题外，它还可能会混淆其他人阅读您的代码并且不熟悉此规则。

Apart from possible problems with browsers, it might also confuse others who read your code and are not familiar with this rule.

FWIW，当然您总是可以使用保留关键字作为字符串：

FWIW, of course you can always use reserved keywords as strings:

var a = {'delete': 'foo'};
alert(a['delete']);

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