feat: Support Cmi5 from the backend

[emmanuel]

Building on #264, this adds an AbstractCmi5 superclass and defines its constructor() to accept LaunchParameters, then make Cmi5 extend that class and contain all window.location references in the Cmi5 subclass.

I'm open to feedback or reworking this. I wanted to get the conversation started with a concrete working implementation to discuss.

Also, I structured this to stack after #264, so please look at the one commit that's distinct in this PR.

[CookieCookson]

@emmanuel Thanks for your contribution, this looks really great!

Would there need to be any additional helper methods for backend scenarios? I'm unsure how you're going to consume the BackendCmi5 class and the role it plays in the wider project.

The general approach here is spot on, if we could get it split up so we have the classes in different files we would have a good candidate.

[emmanuel]

@CookieCookson I think this is ready for another look now that the first PR landed.

To answer your question: I'm working on a project where we have an AU provider that has a backend component: it is consumed via the browser but scoring and some interactions occur on our backend. Because the launch is initiated via query parameters, one of the first steps when an AU is launched is that our frontend calls our backend with the Cmi5 launch parameters, then we send all xAPI statements from the backend. Not long ago I moved our project over to use your XAPI.js lib from our backend.

I would like to adopt (something like) the BackendCmi5 implementation to handle communication with the LRS (submitting xAPI statements, both cmi5 defined and cmi5 allowed). And then separating the functionality in Cmi5.ts from the assumptions about executing in the browser are the intent of this PR!

[emmanuel]

There's a 405 from codeclimate; I don't know what that means.

Also, coverage may have marginally decreased (because lines may have grown slightly by me moving things around, and I didn't add any test coverage to offset that).

[CookieCookson]

Sounds great, thanks for clearing up the use case!

Please ignore codeclimate, I've found it to be quite counter productive at times and will most likely end up removing it in the near future. I can bypass the results for it in the CI so we won't have to make any code changes for it.

I'm away for the weekend now but I'll pick this up next week for another review 👀

[emmanuel]

@CookieCookson — howdy! Just checking in.

Is this tracking towards landing? And is there anything further you'd like to see done on this PR?

[CookieCookson]

@emmanuel Great stuff, it's all merged in now! I'll do some testing with the CMI5 demo project to ensure its all working as expected for client-side.

EDIT: Demo project seems to be working as before!

[CookieCookson]

@emmanuel Looking at the rollup output, do you need some additional exports for the AbstractCmi5 class so it can be directly imported into your backend code?