7.3. JavaScriptCollectionProxy

The JavaScriptCollectionProxy is the most difficult part of RJS to understand and work with. This section will first cover some of the trickier aspects of the enumerable support and the actual reference will begin. This will help you avoid trouble and maintain your productivity.

7.3.1. Block Variables and the Enumerable methods

JavaScriptGenerator#select() returns an instance of the JavaScriptElementCollectionProxy class. JavaScriptElementCollectionProxy inherits from JavaScriptCollectionProxy, which provides all of the functionality. The trickiest part about the collection proxy enumerable methods is the code that goes within the block. The code within the block is translated into a JavaScript iterator function. Another tricky aspect of the enumerable block is that you can use any variable names you like for the block parameters, but in the generated JavaScript iterator function the variable names used are always value and index. This rule applies to any expression you use within the block that isn't a simple method called on the proxy object.