Enable multiple dynamic keys with {{get}}

[Panman82]

Currently, I believe the {{get}} helper is limited to one dynamic key.

{{get someObject keyA}}

I have a case where there are multiple dynamic keys in a path. Eg: foo.bar.baz The current workaround is to use multiple, nested "get's".

{{get (get someObject keyA) keyB}}

What I propose is that the get helper use the remaining params as individual keys.

{{get someObject keyA keyB}} // == someObject.keyA.keyB

It almost acts like a concat helper, but that is not allowed in the current implementation.

{{get someObject (concat keyA '.' keyB)}}

[rwjblue]

Nested (get's seem OK/appropriate here to me. Why does that seem wrong to you?

[stefanpenner]

@rwjblue im curious why the path variation is disallowed .

[Panman82]

@rwjblue It just seems like it would be a nice shorthand for deep key paths. And it just reads better, no?

There is just something about nested gets, even using the concat option, that makes by brain go "ick". And the multiple params just seems logical to me. Perhaps others feel differently.

[mmun]

@rwjblue I don't like this (get should act like Ember.get) but on the other hand, this is something that's easy to ast-transform if we have a better solution in the future.

[Panman82]

@mmun So this.get('foo.bar.baz'); is not the same??

[mmun]

The same as?

[btecu]

What do you use the {{get}} helper for?

[mmun]

@btecu The {{get}} helper is used when you need a dynamic member lookup, much like foo[bar] in JS. Examples:

• {{get obj somePath}} is the template equivalent of Ember.get(obj, somePath).
• {{get obj "foo.bar"}} is equivalent to {{obj.foo.bar}}.

From what I've heard it's typically used when dealing with polymorphic models. Often with dynamic forms.

[Panman82]

@mmun So, re-reading everything, sounds like you feel it should at least support {{get obj "foo.bar"}}, currently not allowed. That would then enable the use of {{get obj (concat dynamicFoo '.' dynamicBar)}}. But what do you mean about ast-transform?

[mmun]

@Panman8201 If that doesn't work I am sad. It should! Forget about the AST transform, I misunderstood the problem. We both agree that {{get obj (concat dynamicFoo '.' dynamicBar)}} should work.

[rwjblue]

@mmun - I believe @Panman8201 mentioned this in the intro description, but we currently disallow the key to include a period. See https://github.com/emberjs/ember.js/blob/v2.1.0-beta.2/packages/ember-htmlbars/lib/keywords/get.js#L123.

[Panman82]

Is it as simple as removing that assert? I don't see anything else holding back periods.

As for multiple dynamic keys, could that all be handled in the buildStream() function? Maybe by changing this line to something like:

const objRef  = params[0];
const pathRef = params.slice(1).join('.');

That would allow for either {{get obj foo bar}} or {{get obj (concat foo '.' bar)}}. I realize the multiple dynamic keys option isn't that popular with ya, but I'm just trying to figure out how that could be enabled.

[rwjblue]

Should be fully addressed by #12323.