如何在浏览器中使用 CoffeeScript 正确确定函数范围？
(->
jQuery ->
globalThis = @
$('#emailTypes').change ->
globalThis.toggleEmailOptions()
toggleEmailOptions = ->
$('.emailTypeOptions').fadeOut 'fast', ->
for emailType in $('#emailTypes').val()
$("##{emailType}Options").fadeIn()
).call this
这是我的 .coffee 文件。但是，toggleEmailOptions 函数不在 jQuery ready 的范围内。我怎样才能使其在范围内？
(->
jQuery ->
globalThis = @
$('#emailTypes').change ->
globalThis.toggleEmailOptions()
toggleEmailOptions = ->
$('.emailTypeOptions').fadeOut 'fast', ->
for emailType in $('#emailTypes').val()
$("##{emailType}Options").fadeIn()
).call this
That's my .coffee file. However, the toggleEmailOptions function isn't in scope of the jQuery ready. How can I make it in scope?
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评论（3）
来自 http://jashkenas.github.com/coffee-script/
或者如果您使用的是 node.js ，则绑定到
exports。对于你的例子，它变成：
From http://jashkenas.github.com/coffee-script/
Or bind to
exportsif you're using node.js .For your example, it becomes:
我认为你不需要换行，因为咖啡脚本已经做到了，这是我重写你的代码的方式：
I think you don't need to wrap because coffeescript already do it, here's how I would rewrite your code:
这里有几个问题。一是您似乎假设
@/this是 jQuery 回调中的全局对象 (window)。但很容易看出事实并非如此：请记住，可以在库想要的任何上下文中调用回调。在本例中，
@是文档。并且document.toggleEmailOptions不存在。此外，如果您希望
toggleEmailOptions成为全局变量，则需要将其附加到window（或@/this，因为@ 是文件最外层范围中的 window）。这是因为当您只编写toggleEmailOptions = ...时，CoffeeScript 使用var声明将其范围限定在文件内。通过查看编译后的 JS 很容易看出这一点：var始终位于其作用域的顶部。幸运的是，文件范围无论如何都是您想要的。所以基本上：不要想太多！你想要的是：
其余的保持原样。
There are a couple of problems here. One is that you seems to be assuming that
@/thisis the global object (window) from the jQuery callback. But it's easy to see that it isn't:Remember that callbacks can be called in whatever context the library wants. In this case,
@isdocument. Anddocument.toggleEmailOptionsdoesn't exist.Further, if you want
toggleEmailOptionsto be a global, you need to attach it towindow(or@/this, since@ is windowin the outermost scope of your file). That's because when you just writetoggleEmailOptions = ..., CoffeeScript scopes it within the file using avardeclaration. It's easy to see this by looking at the compiled JS:vars are always at the top of their scope. Fortunately, file scope is what you wanted anyway.So basically: Don't overthink it! What you want is:
and leave the rest as it is.