JSLint抱怨重新定义undefined [英] JSLint complains about redefining undefined

问题描述

undefined 在技术上可以重新定义，因此它不是保留字。因此，我通常在匿名函数中编写代码，强制 undefined 成为未定义的变量，如下所示：

undefined is technically able to be redefined, so it is not a reserved word. As a result, I usually write code in an anonymous function that forces undefined to be an undefined variable, as so:

(function (undefined) {
    "use strict";
    var o = {
        test: "testvalue"
    };
    if (o.test === undefined) {
        // Do stuff here
    } else {
        // Do other stuff there
    }
}());

然而， JSLint 提到以下错误：

Problem at line 1 character 15: Expected an identifier and instead saw 'undefined' (a reserved word).

为什么JSLint抱怨 undefined 是一个保留字，当代码可以任意重新定义变量？我知道你可以使用 typeof x ===undefined;我只是想知道为什么这个方法不起作用。

Why does JSLint complain about undefined being an reserved word, when code can arbitrarily redefine the variable? I know that you can use typeof x === "undefined"; I just wanted to see why this method wouldn't work.

推荐答案

你的方法 工作。仅仅因为JSLint不喜欢它并不会使它成为一个主要的罪。

Your method does work. Just because JSLint doesn't like it doesn't make it a cardinal sin.

尝试 JSHint （为了更加理智）。

Try JSHint instead (for more sanity).

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