One of the things that we care about a lot in datajs is in being practical and enabling better productivity. As such, we don't think you should spend a lot of time pouring over the library documentation to figure out how to put it to use.
Instead, we build some high-level pages with important information, and put together a set of samples that you can use to get up and running quickly. The samples cover using OData, the storage API, and the cache API. They try to show some good best practices, like how to organize UI, in-memory objects and server-data representations so you have cleaner, more maintainable code.
But of course you don't have to rebuild things from the ground up to use datajs to make your site better. You can add a cache on a page to make some lookups faser. You can add preferences locally so the user doesn't have to round-trip to the server to keep them around. You can have input on the side send structured data to your server, or query from it, without having to start from scratch - there is no "page model" associated with datajs, so you can simply pick and choose what you want to get started with and then take it from there.