为什么注释掉这段代码的alert()行会导致它失败？

发布于 2024-10-14 13:36:39 字数 963 浏览 2 评论 0原文

我在 javascript 方面遇到了一个非常奇怪的问题。如果您使用以下代码并运行它，它将正常运行，不会出现任何错误，但如果您注释第一个 alert，它将在第 5 行抛出错误 (var _board = Bomber. BoardFactory.getBoard();) 说 BoardFactory 不存在（请记住，在第一个警报中，所有内容都运行没有错误）。我已经能够使用 Firefox 和 Chrome 重现这种确切的行为。

Bomber = {};

Bomber.Game = function () {
    var self = {};
    var _board = Bomber.BoardFactory.getBoard();

    self.init = function () {};
    self.start = function () {};

    return self;
}

alert("2");

(function () {
    var instance;

    Bomber.BoardFactory = {};
    Bomber.BoardFactory.getBoard = function () {
        if (!instance)
            instance = new Bomber.Board();
        return instance;
    };
})();

alert("3");

Bomber.Board = function () {
    var self = {};
    return self;
}

$(document).ready(function () {
    var game = Bomber.Game();
    game.init();
    game.start();
});

我的问题是，什么可能导致这种奇怪的行为？警报调用到底是如何让它识别 Bomber.BoardFactory 的呢？

原文

I have a very odd problem with javascript. If you take the following code and run it, it will run fine without any error, but if you comment the first alert, it will throw an error at line 5 (var _board = Bomber.BoardFactory.getBoard();) saying BoardFactory doesn't exist (remember that with the first alert everything was running without error). I have been able to reproduce this exact behavior with Firefox and Chrome.

Bomber = {};

Bomber.Game = function () {
    var self = {};
    var _board = Bomber.BoardFactory.getBoard();

    self.init = function () {};
    self.start = function () {};

    return self;
}

alert("2");

(function () {
    var instance;

    Bomber.BoardFactory = {};
    Bomber.BoardFactory.getBoard = function () {
        if (!instance)
            instance = new Bomber.Board();
        return instance;
    };
})();

alert("3");

Bomber.Board = function () {
    var self = {};
    return self;
}

$(document).ready(function () {
    var game = Bomber.Game();
    game.init();
    game.start();
});

My question, is what can possibly cause this odd behavior ? How on earth is it possible that an alert call makes it recognize the Bomber.BoardFactory ?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

旧故 2024-10-21 13:36:39

我通过 jslint 运行它，修复了错误（2 个缺少分号和 if 上缺少 {}）

现在它似乎可以工作

Bomber = {};

Bomber.Game = function () {
    var self = {};
    var _board = Bomber.BoardFactory.getBoard();

    self.init = function () {};
    self.start = function () {};

    return self;
};

//alert("2");

(function () {
    var instance;

    Bomber.BoardFactory = {};
    Bomber.BoardFactory.getBoard = function () {
        if (!instance){
            instance = new Bomber.Board();
        }
        return instance;
    };
})();

//alert("3");

Bomber.Board = function () {
    var self = {};
    return self;
};

$(document).ready(function () {
    var game = Bomber.Game();
    game.init();
    game.start();
});

发生的情况是在定义 Bomber.Game 后您缺少最后一个分号，所以接下来是 (function()....等等，所以它认为你正在调用该函数。

如果你在那里有警报，你会被自动分号插入保存。

I ran it through jslint, fixed the errors (2 missing semicolons and missing {} on your if)

Now it seems to work

Bomber = {};

Bomber.Game = function () {
    var self = {};
    var _board = Bomber.BoardFactory.getBoard();

    self.init = function () {};
    self.start = function () {};

    return self;
};

//alert("2");

(function () {
    var instance;

    Bomber.BoardFactory = {};
    Bomber.BoardFactory.getBoard = function () {
        if (!instance){
            instance = new Bomber.Board();
        }
        return instance;
    };
})();

//alert("3");

Bomber.Board = function () {
    var self = {};
    return self;
};

$(document).ready(function () {
    var game = Bomber.Game();
    game.init();
    game.start();
});

What's happening is you're missing the final semicolon after you define Bomber.Game, so the next thing is (function()....etc, so it thinks you're calling the function.

If you have the alert there you are saved by automatic semicolon insertion.

回复收藏 0 原文