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    <p>One slight gotcha to be aware of is that the object system in OpenLayers uses a function called initialize() as the constructor, so in order to have CoffeeScript's super keyword work correctly when you extend OpenLayers classes, you'll need to decorate them. I use the following function for this:</p> <pre><code>window.CompatibleClass = (cls) -&gt; class Wrapped constructor: -&gt; # Call the OpenLayers-style constructor. cls::initialize.apply @, arguments # Copy prototype elements from OpenLayers class. Wrapped::[name] = el for name, el of cls:: Wrapped </code></pre> <p>Now you can extend an OL built-in like so:</p> <pre><code>class MySpecialFeature extends (CompatibleClass OpenLayers.Feature.Vector) constructor: -&gt; super new OpenLayers.Geometry.Point 0, 0 CLASS_NAME: "MySpecialFeature" </code></pre> <hr> <p>EDIT: Just to clarify, the two alternatives to wrapping the class like this are to use the OpenLayers class system as-is, and miss out on some of the syntax benefits of CoffeeScript, or to manually call the initialize function in each constructor, which feels more brittle, and spreads around the dependency, rather than concentrating it in a single decorator.</p> <p>Using the OpenLayers class system as-is, in CoffeeScript:</p> <pre><code>MySpecialFeature = OpenLayers.Class OpenLayers.Feature.Vector, initialize: -&gt; # Call super using apply, as is convention in OpenLayers OpenLayers.Feature::initialize.apply @, new OpenLayers.Geometry.Point 0, 0 ... ... </code></pre> <p>Alternatively, using CoffeeScript classes, but extending an OpenLayers class un-decorated:</p> <pre><code>class MySpecialFeature extends OpenLayers.Feature.Vector constructor: -&gt; # Call inherited initialize(). @initialize.apply @, new OpenLayers.Geometry.Point 0, 0 ... ... </code></pre> <p>Neither of these methods will be as idiomatic or recognizable to other developers, either of OpenLayers or CoffeeScript. I stand by my recommendation of a wrapper which allows native super() use in calling OpenLayers constructors.</p>
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    1. COI seems like you're adding unneeded complexity and overhead (iterates twice?). Also, the OL api/source is subject to change at any time potently breaking your code. IMHO the OL built in inheritance system is perfectly fine and there is no reason to abstract it.
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    2. COI disagree. I've edited my answer to help better explain the benefits of this approach over the two alternatives.
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    3. COI'm not saying yours doesn't look better. It's semantic and elegant. However, when you start extending a library like OL I find sticking to convention saves you a lot of head aches later on. Sugar like this could introduce a lot more "gotchas"
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