Computed property doesn't update - ember.js

I have the following Ember.js code (in a model):
subdata: DS.hasMany('App.Subdata'),
message_subdata: function() {
return this.get('subdata').filterBy('tag', 'message');
}.property('subdata', 'subdata.#each')
This worked just fine in RC7. In RC8+, I know they made changes to the way that observers fire, but for the life of me, I can't figure out how to get it working again. I know it says to make sure to call get before observing the property, but I'm using this property in a template, so doesn't the template have to get the property?
Right now, when the page first loads, none of the data gets shown because none of the subdata is loaded yet. That's how it's always been. But in RC7, as soon as the records were loaded, it would fire the observers and update the page. Now, for some reason, the observers aren't being update and the page won't update. The only way I can seem to force it to update is by changing the subdata property (or simulating a change with notifyPropertyChange).
How can I get my properties to work as they did in RC7?
EDIT: I thought I would give a quick update on how I did sorting AND filtering. It's probably not the best way, but I fiddled for a while to land on this solution.
subdata: DS.hasMany('App.Subdata'),
message_subdata_filtered: Ember.computed.filterBy('subdata', 'tag', 'message'),
message_subdata: Ember.computed.sort('message_subdata_filtered', function(a,b) {
return a.get('timestamp') - b.get('timestamp');
});
There might be a way to do it in one line, but this works for me.

I guess the new way of doing computed arrays is by using something like this:
subdata: DS.hasMany('App.Subdata'),
message_subdata: Ember.computed.filterBy('subdata', 'tag', 'message')

Related

Not possible to use shorthand route handlers if RestSerializer is used? (ember-cli-mirage)

I set up a simple Ember Twiddle to show you my error that is occurring when trying to update a model.
It's considerable that I'm using ember-cli-mirage for mocking the data.
According to the docs, I created a shorthand route that should handle the PUT request.
It does, but with the error: Your handler for the url /api/shops/1 threw an error: Cannot convert undefined or null to object
When using the JSONAPISerializer, everything is working with shorthands (mirage/config.js) and I'm able to update models, but in my case I have to use the RESTSerializer with serialized IDs in the responses.
The request payload when I'm sending the model's attrs are without Id at the end of the property name, f.e.:
// attrs object in PUT request
{
name: "Shop 1",
city: "1" // belongsTo relationship,
}
Now Mirage is trying to find those properties on the respective database model that has to be updated, but cannot find it, because in the database it's cityId and not just city...
I also found this issue report and it’s working, but I was hoping I could avoid something like this. As far as I can remember, in previous versions of ember-cli-mirage (v0.1.x) it was also not needed to override the normalize method in the serializer to be able to make use of the RestSerializer with serializedIds…
My question is:
Is there a way to stick to shorthand route handlers only, or do I really have to write a helper or other custom solution only because I have to use the RestSerializer?
That would be really sad, but at least I would know then.
Thanks for your support!
Short answer: it looks like you need the custom serializer for now until the bug fix for it is merged.
Long answer: that issue looks to be an issue that occurred in the 0.2 -> 0.3 upgrade for Mirage, likely because of underlying DB changes made in Mirage. It'll probably get fixed, but for now you'll need to work around it.

Ember: Ember Data results into components

On my route im requesting via ember-data some records. Lets say the model-type is 'item'.
model: function(){
return this.get('store').find('item');
}
now ive got a component named 'my-foo' which should use the records to do something with the data. Therefore Im calling the component like that:
{{my-foo myItems=model}}
in my routes template. In the components js part, Im trying to get the myItems-field and iterate over them.
this.get('myItems').forEach(...);
Unfortunalety its not clear for me if the model i want to overgive to the component is an collection from records or just a single record (since on some routes the model is the result of store.find('item') on other store.find('item', 23424).
How can I check what kind of data arrives in the component.
(Also Im wondering what kind of object is it since im using ember-data. Is it a DS.recordarray or a promise or something else at this time?)
I can see two solutions to the problem:
Making component aware of the form that model receives
Checking and/or adjusting data type in component (in my opinion better default scenario)
As for making component aware - you could go with 2 approaches. Either differentiate in a way how your component take arguments, so there could be:
{{my-foo myItems=model}} - when you expect to receive multiple items
{{my-foo item=model}} - when you expect to receive single one
And then work accordingly further on, or - the second approach - is to actually split component (while extracting shared part to a different structure) so you would have my-foo for single items and my-foo-array for multiple.
Advantage of this approach is that you don't deal with what-if-multiple logic, that might grow to something unmanagable later on, yet usage of it is dependant on project requirements.
As for checking and/or adjusting - you already have data in, so could make assumption that your data is dirty and sanitize it using computed property. Below example, where single item is wrapped into an array.
export default Ember.Component.extend({
sanitizedItems: Ember.computed('items', function() {
var items = this.get('items');
if(!Array.isArray(items)) {
return [items];
} else {
return items;
}
})
});
Since you're using Ember.Data, depending on your setup, you might get a promise instead of object/array. In this case, you might want to resolve promise using this.get('items').then(function(items) { ... }) before doing sanitization, yet the idea behind is exactly the same.
You can check full example: Gist, Twiddle

I just can't slice Ember Data store output

I'm JS beginner and recently using ember.js for ui development I came across a problem that I can't solve.
I'm trying to reduce amount of posts to fit them on one page. Simply calling slice method on return value of this.get('store').find() doesn't work. I also tried to trim content of return value of all function, but still without success. Any ideas?
You can use the following:
App.YourController = Ember.ArrayController.extend({
arrangedContent: function() {
return this.get('content').slice(0 , 10);
}.property('content')
});
Where YourController is the controller that belongs to your route. So the content will be the resolved promise from this.store.find('modelName'). The arrangedContent property is the place where you modify the content when you want to perform filtering, ordering etc. Without changing the content directly and preserving all the data.
Give a look in that sample http://jsfiddle.net/marciojunior/pwQ5b/
If you really are calling slice on the return value of this.get('store').find you will run into trouble. The find function returns a promise and you need the result the promise resolves to.
You can solve this in one of two ways:
If you are using the standard Ember pattern for loading in your model, you should have a model function defined in your route. This will actually wait until the result is resolved and in your controller you can call slice on this.get('content')
If you are loading your data within the controller you will need to so something like below:
c = this
this.store.find('myModel').then(function(result) {
c.set('paginatedContent', result.slice(0, 10));
});
Here we are waiting for the promise returned by find to resolve to a result before setting the paginated content based on that result.

Emberjs - unable to redefine named, explicitly compiled Handlebars template

As part of an attempt to port a fairly large/complex existing application to the Ember world, I'm generating and compiling named Handlebars templates dynamically, and associating views with them, using the technique:
var template = Ember.Handlebars.compile("some handlebars stuff");
Ember.TEMPLATES["myTemplate"] = template;
var view = Ember.View.create({
templateName: "myTemplate"
});
One of the things I'd like to do is be able to recompile new/different Handlebars template markup which overwrites the template named "myTemplate" and have it be accessible to views at that name.
I'm getting unexpected results trying to do this - a couple fiddles that illustrate the problems:
First fiddle - Shows what happens if you wait before rendering a view after the named template contents have changed.
Second fiddle - Shows what happens if there's no delay before rendering a view after the named template contents have changed.
There's obviously some magic under the hood that I'm not understanding. Can anyone shed some light on this?
UPDATE:
I went through the source code for Ember.View and the container module, and came to realize that I could solve the problem in the First fiddle by overriding the "template" computed property in a way that skips the container cache lookup. I've put up another fiddle here to demonstrate the solution I found.
This seems to be working the way I'd like it to - but - it feels like I might be fighting with the framework and "unhooking" from the container in a way that might bite me later. Is there a better, more Ember-esque way to accomplish what I'm trying to do? Will the hack I found break things?
UPDATE 2
I've also discovered that it's also possible to simply call
view2.get('container').reset();
before appending view2 in the First fiddle. Seems cleaner/safer, but is it "legal"? I've updated the First fiddle to illustrate this.
(in the second fiddle, both views show the second template)
This is because view1.appendTo($("#target")); just schedules the append, actual view rendering does not happen until end of the run loop. Before that happens, you've set Ember.TEMPLATES["myTemplate"] = template2;
(in the first fiddle, both views show the first template)
Pretty sure this is because ember container caches template fx, but not 100% on that. Checking...
I'm going to call this one answered. As I mentioned in my second comment, I'm using the solution shown in this fiddle in my project, along these lines:
mYiew.get('container').reset();
There's some discussion about the container not being intended to be used as an API here: https://github.com/emberjs/ember.js/commit/5becdc4467573f80a5c5dbb51d97c6b9239714a8 , but there doesn't seem to be any mention of using the container from Views for other use cases.
Also, a View's container can be accessed directly (at ".container") - meaning the devs haven't made it "hard" to get to the way they have for an Application's ".__ container __". This might suggest something about how they intend it to be used.
Since a View having the ability to clear its cache whenever it wants to doesn't seem to me to be unreasonable or a bad practice, I'm using the above mentioned solution...at least until someone sets me straight with a better idea (or a cache API).

How to set a controller property and update a template in Ember.js

I am trying to show a TopController property in a TopView template. In TopView, I have sectionBinding: 'controller.section'.
From my understanding of Ember.js, in TopView, the controller property should refer to my TopController. Yet it seems to refer to ApplicationController? Read on:
In my router, I have router.set('topController.section', 'index');... But that doesn't seem to do anything in this case. Changing it to router.set('applicationController.section', 'index'); works and the {{section}} part in the TopView template changes to "index".
I have created two fiddles showing my issue. The first one doesn't work:
FAULTY -> http://jsfiddle.net/8tQ4q/4/
The second one does work:
WORKS -> http://jsfiddle.net/8tQ4q/5/
The only difference is the topController / applicationController part in router.set(). Any idea what I am doing wrong?
I'm not sure why you're expecting topController to be connected to TopView. You haven't done anything to make this connection. I think you may be confused because connectOutlet('top') would create a TopView that is connected to topController. However, you aren't doing this anywhere in your app.
You also don't need the sectionBinding. If you have a controller defined on your view, it will be the default context.
I think what you want to do is this:
router.get('topController').set('section', 'index');