警告-危险使用全局this对象 [英] WARNING - dangerous use of the global this object

问题描述

在Google Closure编译器中，我得到警告

In Google Closure Compiler I get the warning

警告-危险使用全局this对象

WARNING - dangerous use of the global this object

这里是一个例子.错误行和偏移量是指单词this

Here is an example. The error line and offset refers to the beginning of the word this

function aToggle() {
  if(shown)
    toggle.show()
  else
    toggle.hide()
  $(this).text(shown ? 'Click to hide' : 'Click to show')
  shown = !shown
}
link.onclick = aToggle

我只是将其更改为匿名方法，但是我在文件的其他位置重复使用aToggle，因此需要对其进行命名.

I would just change it to an anonymous method, but I am re-using aToggle elsewhere in the file, so it needs to be named.

我可以将aToggle标记为/**@constructor*/，但是它不是构造函数.我是否可以使用其他注释来消除此警告，还是在将其标记为构造函数还是出现一堆无用的警告之间卡住了?

I could mark aToggle as /**@constructor*/ -- but it is not a constructor. Is there another annotation I can use to eliminate this warning, or am I stuck between marking it as constructor or having a bunch of useless warnings show up?

推荐答案

编辑:我一直在阅读《封闭:权威指南》，而我只是意识到，您可以简单地添加 /** @this {Element} */批注在事件处理程序之前Closure编译器停止抱怨.

Edit: I've been reading Closure: The Definitive Guide, and I just realized that you can simply add the /** @this {Element} */ annotation before your event handler to make Closure Compiler stop complaining.

请参见 Closure Compiler警告参考.当您在未注释/** @constructor */或类的prototype中的函数中使用this时，Closure Compiler会发出此警告.编译器假定在另一个对象的上下文中调用函数时，您永远不会使用this(这是事件回调的作用).

See the Closure Compiler warning reference. The Closure Compiler gives this warning when you use this within a function that is not either annotated /** @constructor */ or is within the prototype of a class. The compiler assumes that you'll never use this when a function is called in the context of another object (which is what event callbacks do).

您可能需要更改某些地方以使Closure Compiler停止抱怨此警告:

Some places that you might have to change to make Closure Compiler stop complaining with this warning:

• 请勿直接使用link.onclick = ...，因为您必须弄乱this和e || window.event.相反，请使用jQuery包装事件处理程序，因为 jQuery的事件对象具有e.currentTarget .
• 如果要在jQuery.each中使用this，请将this替换为函数的第二个参数.例如jQuery.each([1, 2, 3], function(i, val) { ... val ... };.

• Don't use link.onclick = ... directly, because you have to mess with this and e || window.event. Instead, use jQuery to wrap the event handler, since jQuery's event object has e.currentTarget.
• If you're using this within a jQuery.each, replace this with the second parameter of your function. E.g., jQuery.each([1, 2, 3], function(i, val) { ... val ... };.

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