Now that we have a kind of API and a contract between server side and JS/Client side, we need to be much more explicit (at first, in comments) about what that contract is. 
So, at a bare minimum, we should have:
- the data model (JSON produced by API / consumed by JS to build the datatable). Ideally, that structure should be directly derived from an immutable case class, so that we do have the contracts checks by the compiler (i.e, some where we have a JsLineInfo case class with a "toJs" method, and the lineInfo method produce that)
- where it is produced, 
- where it is used (as for now, it's all at the same place).