Automatic unloading of models in long-lived apps

[BryanCrotaz]

I'm building an app that will run for years at a time, so has to be ultra robust.

I'm looking at writing an extension for ember-data that will declaratively unload models when they're not needed any more (no routes or components need them). For example you could mark a model as being unloadable 10 minutes after its last use.

So the big question is how to detect that a model is no longer needed (let's assume that it's ok to reload it from the server if we need it in future). Would it be safe to say that a model can be unloaded if it has no observers actively watching it? Or is there a way of using a model that wouldn't involve an observer?

[stefanpenner]

I don't believe this is possible without explicit ref counting done in user land, that is unless you are running on a platform that supports native WeakMaps.

[ReyAyanami]

Sorry, but is this function request still actual? Since major number of current browsers support WeakMap's maybe now it is possible to implement auto-unload

[stefanpenner]

@ReyAyanami well, sorta. We are still missing some features, e.g. WeakMap make some of it possible but not all. Def an area that requires more exploration though.

[runspired]

We've implemented internal ref counting, we'er still missing some features but even in terms of giving app-devs high level tools for doing this on their own we don't have a great story yet. I've left some thoughts here: https://github.com/emberjs/data/issues/4938#issuecomment-383340318

[runspired]

Going to close this in favor of #8162 which will require either an RFC or some other library to explore via EmberData's public APIs. This is definitely achievable and if someone comes up with a good pattern we'd consider it for core.