CoffeeScript 混乱？ （KeyUp Jquery）
我刚刚开始使用 CoffeeScript 来看看有什么大惊小怪的，我喜欢它。然而，在将我的旧脚本转换为咖啡时遇到了一个问题：
$(function() {
$(create_MP).keyup(function(e){
if(e.which == 16) {
isShift = false;
}
});
});
这是我之前的 JQuery，所以我尝试将其转换为咖啡脚本：
jQuery ->
$(create_MP).keyup(e) ->
if e.which == 16
isShift = false
但是在打开控制台时出现此错误：
application.js :23Uncaught TypeError: 对象 [object Object] 没有方法 'keyUp' 有
什么想法吗？
I've just started using coffeescript to see what all the fuss is about and I love it. However there is a problem I had when converting an old script of mine over to coffee:
$(function() {
$(create_MP).keyup(function(e){
if(e.which == 16) {
isShift = false;
}
});
});
That's the JQuery that I had before so I tried to transform it into coffeescript:
jQuery ->
$(create_MP).keyup(e) ->
if e.which == 16
isShift = false
But I get this error when opening the console:
application.js:23Uncaught TypeError: Object [object Object] has no method 'keyUp'
Any ideas?
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评论（2）
无论如何，该代码都是错误的。您发布的 CoffeeScript 与此等效：
也就是说，您正在调用
keyup(e)的结果并向其传递一个函数。您想要的是使用该函数作为参数来调用keyup()。解决这个问题的最简单方法就是在keyup和(e) ->之间添加一个空格。That code is wrong regardless. The CoffeeScript you posted is equivalent to this:
That is, you're calling the result of
keyup(e)and passing a function to it. What you want is to callkeyup()with the function as an argument. The simplest way to fix it would just to put a space betweenkeyupand(e) ->.您在评论中指出的问题并不是您唯一的问题。您需要在
(e)之前添加一个空格，否则 CoffeeScript 会认为您正在尝试使用参数e调用keyup函数。您想说的是：如果没有空格，您的 JavaScript 将如下所示：
这没有任何意义，因为
keyup(e)不会返回函数。但是，如果添加空格，那么(e) ->就会成为接受单个e参数的匿名函数的定义：这不仅有意义，它也会做你想要它做的事情。
The problem you note in your comment isn't your only problem. You need to a space before
(e)or CoffeeScript will think you're trying to call thekeyupfunction with an argument ofe. You want to say this:Without the space, your JavaScript will look like this:
and that doesn't make any sense since
keyup(e)won't return a function. But, if you add the space, then(e) ->becomes a definition of an anonymous function which takes a singleeargument:and not only does that make sense, it does what you want it to do as well.