CoffeeScript Confusion? (KeyUp Jquery) - coffeescript

Question

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?

Answer 1

That code is wrong regardless. The CoffeeScript you posted is equivalent to this:
jQuery(function() {
$(create_MP).keyup(e)(function() {
if (e.which == 16) {
isShift = false
}
}
}
That is, you're calling the result of keyup(e) and passing a function to it. What you want is to call keyup() with the function as an argument. The simplest way to fix it would just to put a space between keyup and (e) ->.
jQuery ->
$(create_MP).keyup (e) ->
isShift = false if e.which is 16

Answer 2

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 the keyup function with an argument of e. You want to say this:
jQuery ->
$(create_MP).keyup (e) ->
if e.which == 16
isShift = false
Without the space, your JavaScript will look like this:
jQuery(function() {
return $(create_MP).keyup(e)(function() {
// ...
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 single e argument:
jQuery(function() {
return $(create_MP).keyup(function(e) {
// ...
and not only does that make sense, it does what you want it to do as well.