CoffeeScript is a programming language that compiles to JavaScript. It allows for writing code using less syntax which gets checked at compile time. While a compile step is required, CoffeeScript can be used to write code for Rails and other JavaScript frameworks more concisely. It demonstrates converting typical jQuery code snippets to more concise CoffeeScript equivalents. CoffeeScript helps minimize and concatenate JavaScript files, though debugging is still challenging.

1. CoffeeScript in 5mins
@mackato - 2011.09.14 #izakaya.js
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2. “CoffeeScript is a little language
that compiles into JavaScript.”
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3. Pros
less code
compile-time code check
compiles into pure JavaScript
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4. Cons
require compile process
little strange syntax
debugging is too hard,
yet.
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5. Use Case
Rails 3.1
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6. Use Case
Any other JavaScript Frameworks
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7. JS to CoffeeScript
$(document).ready(function() {
init();
some();
$("a.link").click(function() {
$(this).fadeOut("slow", function () {
$(this).remove();
});
});
});
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8. JS to CoffeeScript
$(document).ready(function() {
init()
some()
$("a.link").click(function() {
$(this).fadeOut("slow", function () {
$(this).remove()
})
})
})
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9. JS to CoffeeScript
$(document).ready function()
init()
some()
$("a.link").click function()
$(this).fadeOut "slow", function ()
$(this).remove()
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10. JS to CoffeeScript
$(document).ready ->
init()
some()
$("a.link").click ->
$(this).fadeOut "slow", ->
$(this).remove()
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11. JavaScript build is necessary
without CoffeeScript
concatenate
<script src="/javascripts/jquery.js"></script>
<script src="/javascripts/jquery.min.js"></script>
<script src="/javascripts/application.js"></script>
<script src="/javascripts/all.js"></script>
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12. JavaScript build is necessary
without CoffeeScript
minify
(function( window, undefined ) {
var document = window.document,
navigator = window.navigator,
location = window.location;
(function(a,b){function cy(a){return f.isWindow(a)?a:a.nodeType===9?
a.defaultView||a.parentWindow:!1}function cv(a){if(!cj[a]){var b=f("
+">").appendTo("body"),d=b.css("display");b.remove();if(d==="none"||
d===""){ck||
(ck=c.createElement("iframe"),ck.frameBorder=ck.width=ck.height=0),c
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13. JavaScript build is necessary
without CoffeeScript
concatenate minify
js
js js js
js
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14. JavaScript build is necessary
without CoffeeScript
compile concatenate minify
coffee js
coffee js js js
coffee js
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15. Cons
require compile process # not cons
little strange syntax
debugging is too hard,
yet.
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