关键字"new"在JavaScript中有什么副作用? [英] What side effects does the keyword 'new' have in JavaScript?

问题描述

我正在开发jQuery插件，却出现此 JSLint 错误:

I'm working on a plug-in for jQuery and I'm getting this JSLint error:

Problem at line 80 character 45: Do not use 'new' for side effects.

(new jQuery.fasterTrim(this, options));

我没有太多运气找到有关此JSLint错误或new可能会有的副作用的信息.

I haven't had much luck finding info on this JSLint error or on any side effects that new might have.

我已经尝试过必应给了我2条结果，但是它们都只引用了JSLint源.希望这个问题会改变这一点. :-)

I've tried Googling for "Do not use 'new' for side effects." and got 0 results. Binging gives me 2 results but they both just reference the JSLint source. Hopefully this question will change that. :-)

更新#1: 这里是上下文的更多来源:

Update #1: Here's more source for the context:

  jQuery.fn.fasterTrim = function(options) {
    return this.each(function() {
      (new jQuery.fasterTrim(this, options));
    });
  };

更新#2: 我使用入门jQuery插件生成器作为我的插件的模板，该模板中包含该代码

Update #2: I used the Starter jQuery plug-in generator as a template for my plug-in, which has that code in it.

推荐答案

特拉维斯，我是Starter网站背后的开发人员.

Travis, I am the developer behind the Starter site.

@Pointy碰到头上的钉子.以这种方式编写Starter代码的原因是因为我们确实需要一个新对象，我们只需要在那时不需要存储对它的引用即可.

@Pointy hit the nail on the head. The reason the Starter code is written that way is because we do need a new object, we just don't need to store a reference to it at that point.

只需从

(new jQuery.fasterTrim(this, options)); 

到

var fT = new jQuery.fasterTrim(this, options);

将按照您发现的方式安抚JSLint.

will appease JSLint as you have found.

Starter插件设置遵循jQuery UI模式，即在元素的data集中存储对对象的引用.所以这就是正在发生的事情:

The Starter plugin setup follows the jQuery UI pattern of storing a reference to the object in the data set for the element. So this is what is happening:

1. 创建新对象(通过新对象)
2. 使用jQuery的data:$(el).data('FasterTrim', this)
将实例附加到DOM元素

1. New object is created (via new)
2. The instance is attached to the DOM element using jQuery's data :$(el).data('FasterTrim', this)

对于返回的对象没有用处，因此没有进行var声明. 我将研究更改声明并清理输出，以使JSLint开箱即用.

There is no use for the object that is returned, and thus no var declaration made. I will look into changing the declaration and cleaning up the output to pass JSLint out of the box.

更多背景信息:

使用data存储对象的好处是，我们以后可以随时通过调用$("#your_selector").data('FasterTrim')来访问对象.但是，如果不需要以这种方式在流中访问您的插件(意味着，它是在单个调用中设置的，并且不提供任何将来的交互)，那么就不需要存储引用.

The benefit to storing the object using data is that we can access the object later at any time by calling: $("#your_selector").data('FasterTrim'). However, if your plugin does not need to be accessed mid stream that way (Meaning, it gets set up in a single call and offers no future interaction) then storing a reference is not needed.

如果您需要更多信息，请告诉我.

Let me know if you need more info.

这篇关于关键字"new"在JavaScript中有什么副作用?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！