Code completion based on .jsb2 file?

Does intellij platform support code completion based on .jsb2 files? I know that by default javascript libraries have code completion, but as i'm developing using ExtJS and i'm planning on using the new extjs4 which is supposed to be realeased pretty soon, i doubt code completion will work out of the box. When you create/extend a new class in Extjs 4 you will put the name inside ' ' (eg: 'className' ), which is basically a text.... so i'm guessing code completion will not work.

There's another editor that parses the .jsb2 files provided by extjs framework and based on that it enables code completion.

How would the intellij platform behave in this situation? Will code completion work out of the box, and if not, is there any possibility of implementing code completion based on .jsb2 files?

thanks!