Ability to tell if the result of a findAll had any records from the adapter

[pixelcort]

Currently DS.Store#findAll returns an instance of DS.ModelArray, which does not include an isLoaded property.

Instead, DS.Store#findAll should return something that includes an isLoaded property.

When the adapter returns all the data for the findAll, the isLoaded property on the originally returned result of DS.Store#findAll should change to true.

[pixelcort]

Rationale is I want to be able to determine whether there are genuinely no instances of a model on the server vs just there not being any instances on the client yet.

[wycats]

Just to be clear on semantics, what you're saying is that as soon as a single item for a type was added to the store, all findAll queries for that type should switch to isLoaded?

[pixelcort]

@wycats I'm okay with that, but the problem then is what happens if the server has no instances of that type?

My goal is to display a UI that says "There are no Cars", but I don't want to show this UI while any potential Cars are loading from the initial call to DS.Adapter#findAll.

[MikeAski]

My 2 cents...

I also need some notification mecanism to perform some processing once the findAll has complete results loading.
Such a property would be observable, so processing could be triggered.

I may be wrong, but it seems to me this observation is quite "transient", and it is certainly useless to keep this observation after it has been triggered once.
In this case, what about a more simple "callback" mecanism, that would allow to perform processing once, after all (possible) data from server have been loaded?

@pixelcort Do my need meets yours?

@wycats Would it be ember-idiomatic to have such a callback mecanism?

[MikeAski]

Just found a solution to my problem, which could also match your need, @pixelcort : http://stackoverflow.com/a/9568939/90741

[pixelcort]

@MikeAndrzejewski that works but feels like Store#findQuery is a private method and that we should instead be using Store#find. Your workaround would probably also work with Store#filter with a function that always returns true, and that would guard against implementation detail changes inside of how findQuery works.

However, in any case, this doesn't resolve the issue, which is how do I determine whether the adapter returned no items for a given findAll query, or simply that it hasn't returned yet.

[pixelcort]

Updated title to better reflect issue.

[MSch]

Triggering a event once the ModelArray starts populating and once it has finished populating would cover my usecase perfectly.

[analytically]

+1 this is pretty annoying...

[mmpestorich]

Here's how I worked around this issue.

I created a new DS.Adapter and implemented findAll such that its success callback sets an isLoaded property to true on the DS.RecordArray that is returned and cached in the store.

findAll(store, type) {

    var request = { ... }

    var success = function(data, status, xhr) {
        data = JSON.parse(data);
        store.loadMany(type, data);
        store.typeMapFor(type).findAllCache.set('isLoaded', true);
    }

    $.ajax({ 
        'url': 'data.php',  
        'type': 'POST', 
        'data': {request: JSON.stringify(request)},
        'success': [success],
        'async': async
    });
}

Seems to be working for me. I can now observe isLoaded on a findAll's return value.

[pixelcort]

@mmpestorich nice workaround; I'll try using that next time. Thanks!

[mmpestorich]

I just posted Pull Request #271 that implements isLoaded on DS.RecordArray. With these changes, the resulting array from store.findAll and store.findMany can be used in similar fashion to that of store.findQuery. I've tested it every which way I can think of and it seems to do what I expect of it.

[wagenet]

Looks like f707b6c addresses this.

[mmpestorich]

It does. Thanks.