This is an implementation of Resource Query Language (RQL) that uses ES6 classes. The implementation primarily focuses on the ability to apply an RQL query string against a JSON array.
The original project (in AMD form) can be found at github.com/kriszyp/rql, along with some good documentation. It's some fine stuff, check it out. This query engine sandbox is also useful for learning and testing with the original RQL engine.
See the rql no-dojo repo for temporary documentation.
This code was "borrowed" from RQL, which is licensed under the AFL or BSD license as part of the Persevere project.