I have just begun learning ember.js, I have followed some tutorials and created a working example here:
App.Track.reopenClass({
find: function() {
var tracks = [];
$.ajax({
url: 'http://ws.spotify.com/lookup/1/.jsonuri=spotify:album:6J6nlVu4JMveJz0YM9zDgL&extras=track',
dataType: 'json',
context: this,
success: function(data, textStatus, jqXHR) {
$.each(data.album.tracks, function(index, value) {
track_id = value.href.replace("spotify:track:", "");
tracks.addObject(App.Track.create(value));
// I would rather do something like:
// tracks[track_id] = App.Track.create(value)
});
}
})
return tracks;
}
});
This function hits an API and loops through the returned data to populate the tracks object (tracks.addObject(App.Track.create(value));) and return it.
Rather than getting an ordinary object back from this function, I would like to get an Enumerable / Array so I can manipulate it with filterProperty or pull out tracks by id (There is a track_id which I would like to use as the array index).
All of my attempts to use an array have broken ember's magical ability to update the view when the ajax call populates the tracks.
Can anyone modify http://jsfiddle.net/ZEzwn/ to return an Enumerable (preferably an Array) but still update the view automatically?
As your method already returns an Array (because you have Ember prototype extension enabled), doing:
var tracks = [];
is equivalent to
var tracks = Ember.A();
On ajax request success, you're just populating the array, so you could use Ember.Array methods like filterProperty.
Just one thing about using id as array key, you really SHOULD NOT, as Ryan Bigg says in its blog:
However, if the variant’s id is [something a little higher, like] 1,013,589,413, then you start to run into problems.
In that case, JavaScript would create a one billion, thirteen million, five hundred and eighty-nine thousand, four hundred and fourteen element array. All to store one value in, right at the end.
Ok this is now working, as louiscoquio pointed out, tracks IS an enumerable object and I can do stuff like
tracks.filterProperty('href', 'spotify:track:7x7F7xBqXqr0L9wqJ3tuQW')
tracks.getEach('name')
tracks.get('firstObject')
Related
In JavaScript, one can remove selected elements from an array by traversing it in reverse order and using splice(index, 1) to remove undesired elements. I'm trying to figure out how to do the same thing in Ember.js (without Ember Data).
I have an ArrayController and the associated Route's model function simply returns a JavaScript array. There an action in the controller, along the following lines:
removeElements: function () {
var i, arr = this.get('content'),
i = arr.length;
while (i) {
i -= 1;
if (arr[i].get('flag')) {
array.replace(i, 1);
}
}
This first appears to work in the browser. For example, if I have three elements and mark the first and third to be removed, the browser will leave the second item displayed. However, if I later try to mark the latter, Ember complains with Uncaught Error: Can't remove an item that has never been added.
I used replace() because Ember arrays don't have a splice method, but the docs also say that replace must be implemented in order to be used, but I don't quite understand where I'm supposed to implement it and I haven't found any sample implementations to guide me.
I've also tried various other methods, such as removeObject, removeObjects and more, but none did what I need.
You'd need to create your own array collection and implement replace on that collection (probably extending Ember.Array to get you started).
removeObject should work just fine (granted a little inefficient, though if the size of this list is small it's negligible):
removeElements: function () {
var controller = this,
list = this.toArray();
list.forEach(function(item){
if(item.get('flag')){
controller.removeObject(item);
}
});
}
using removeAt should give you the results you're looking for
removeElements: function () {
var i = this.get('length');
while (i--) {
if (this.objectAt(i).get('flag')) {
this.removeAt(i);
}
}
}
I am very new to ember and what I am trying to do is get the data from the model into an array.
Currently I am doing:
var playerList = App.Player.find().toArray();
But it's not returning me an array of players it's returning an array of the objects? ex:
<App.Player:ember311:1>,<App.Player:ember332:2>,<App.Player:ember338:3>,<App.Player:ember344:4>,<App.Player:ember350:5>,<App.Player:ember356:6>,<App.Player:ember362:7>,<App.Player:ember368:8>
Any help would be appreciated. Thanks!
App.Player.find() returns a promise, and therefore you should wait until your records are fully loaded before doing operations on them. From your question it's not entirely clear how you player objects do look like. But to get to your players, and especially to your player's properties, you could do something like:
var playerList = App.Player.find().then(function (result) {
// This callback will fire when array is loaded
// and this is the correct way to get to the records
result.objectAt(0).get('name'); // assuming "name" is a property of your model
// here you can then loop over your obejcts
result.forEach(function(item) {
console.log(item.get('name'));
});
});
Hope it helps.
I have a fiddle http://jsfiddle.net/kristaps_petersons/9wteJ/2/ it loads 3 objects and shows them in a view. Data is shown alright, but i can not filter it before i show it.
This
nodes: function(){
this.get('controller.content').filter(function(item, idx, en){
console.log('should log this atleast 3x')
})
return this.get('controller.content')
}.property('controller.content')
method is called when template iterates over array of values, but it never goes in to the loop and print console.log('should log this atleast 3x') why is that?
You are trying to replace controller.content while also binding to it. You need to define another property, such as filteredContent and bind it to controller.content. Take a look at how Ember.SortableMixin computes the variable arrangedContent for controllers with a sortProperties variable defined. Using that method as a template I would implement it like this:
filteredContent: Ember.computed('content', function() {
var content = this.get('content');
return this.filter(function(item, idx, en) {
console.log('should log this atleast 3x');
});
}).cacheable()
This should be implemented in the controller, not the view. The controller is the place for data manipulation, computed properties, and bindings.
Then bind the view layout to filteredContent instead of content to show the filtered data. Then both the original content and the filtered content are available.
Ok i got it working, but it feels a bit strange. First i moved method to Controller class and changed it to look like this:
nodes: function(){
console.log('BEFORE should log this atleast 3x', this.get('content.length'))
this.get('content').forEach(function(item, idx, en){
console.log('should log this atleast 3x')
})
console.log('AFTER should log this atleast 3x', this.get('content.length'))
return this.get('content')
}.property('content').cacheable()
as it should be same as buuda's recomedation, because as i understand from docs .poperty() is the same as Ember.computed. As it was still not working, i changed .property('content') to .property('content.#each') and it was working. Fiddle: http://jsfiddle.net/kristaps_petersons/9wteJ/21/ . I guess, that tempate first creates a binding to controller.content and as content itself does not change does not notify this method again, instead template pulls data as it becomes available.
I have a DS.Store which uses the DS.RESTAdapter and a ChatMessage object defined as such:
App.ChatMessage = DS.Model.extend({
contents: DS.attr('string'),
roomId: DS.attr('string')
});
Note that a chat message exists in a room (not shown for simplicity), so in my chat messages controller (which extends Ember.ArrayController) I only want to load messages for the room the user is currently in:
loadMessages: function(){
var room_id = App.getPath("current_room.id");
this.set("content", App.store.find(App.ChatMessage, {room_id: room_id});
}
This sets the content to a DS.AdapterPopulatedModelArray and my view happily displays all the returned chat messages in an {{#each}} block.
Now it comes to adding a new message, I have the following in the same controller:
postMessage: function(contents) {
var room_id = App.getPath("current_room.id");
App.store.createRecord(App.ChatMessage, {
contents: contents,
room_id: room_id
});
App.store.commit();
}
This initiates an ajax request to save the message on the server, all good so far, but it doesn't update the view. This pretty much makes sense as it's a filtered result and if I remove the room_id filter on App.store.find then it updates as expected.
Trying this.pushObject(message) with the message record returned from App.store.createRecord raises an error.
How do I manually add the item to the results? There doesn't seem to be a way as far as I can tell as both DS.AdapterPopulatedModelArray and DS.FilteredModelArray are immutable.
so couple of thoughts:
(reference: https://github.com/emberjs/data/issues/190)
how to listen for new records in the datastore
a normal Model.find()/findQuery() will return you an AdapterPopulatedModelArray, but that array will stand on its own... it wont know that anything new has been loaded into the database
a Model.find() with no params (or store.findAll()) will return you ALL records a FilteredModelArray, and ember-data will "register" it into a list, and any new records loaded into the database will be added to this array.
calling Model.filter(func) will give you back a FilteredModelArray, which is also registered with the store... and any new records in the store will cause ember-data to "updateModelArrays", meaning it will call your filter function with the new record, and if you return true, then it will stick it into your existing array.
SO WHAT I ENDED UP DOING: was immediately after creating the store, I call store.findAll(), which gives me back an array of all models for a type... and I attach that to the store... then anywhere else in the code, I can addArrayObservers to those lists.. something like:
App.MyModel = DS.Model.extend()
App.store = DS.Store.create()
App.store.allMyModels = App.store.findAll(App.MyModel)
//some other place in the app... a list controller perhaps
App.store.allMyModels.addArrayObserver({
arrayWillChange: function(arr, start, removeCount, addCount) {}
arrayDidChange: function(arr, start, removeCount, addCount) {}
})
how to push a model into one of those "immutable" arrays:
First to note: all Ember-Data Model instances (records) have a clientId property... which is a unique integer that identifies the model in the datastore cache whether or not it has a real server-id yet (example: right after doing a Model.createRecord).
so the AdapterPopulatedModelArray itself has a "content" property... which is an array of these clientId's... and when you iterate over the AdapterPopulatedModelArray, the iterator loops over these clientId's and hands you back the full model instances (records) that map to each clientId.
SO WHAT I HAVE DONE
(this doesn't mean it's "right"!) is to watch those findAll arrays, and push new clientId's into the content property of the AdapterPopulatedModelArray... SOMETHING LIKE:
arrayDidChange:function(arr, start, removeCount, addCount){
if (addCount == 0) {return;} //only care about adds right now... not removes...
arr.slice(start, start+addCount).forEach(function(item) {
//push clientId of this item into AdapterPopulatedModelArray content list
self.getPath('list.content').pushObject(item.get('clientId'));
});
}
what I can say is: "its working for me" :) will it break on the next ember-data update? totally possible
For those still struggling with this, you can get yourself a dynamic DS.FilteredArray instead of a static DS.AdapterPopulatedRecordArray by using the store.filter method. It takes 3 parameters: type, query and finally a filter callback.
loadMessages: function() {
var self = this,
room_id = App.getPath('current_room.id');
this.store.filter(App.ChatMessage, {room_id: room_id}, function (msg) {
return msg.get('roomId') === room_id;
})
// set content only after promise has resolved
.then(function (messages) {
self.set('content', messages);
});
}
You could also do this in the model hook without the extra clutter, because the model hook will accept a promise directly:
model: function() {
var self = this,
room_id = App.getPath("current_room.id");
return this.store.filter(App.ChatMessage, {room_id: room_id}, function (msg) {
return msg.get('roomId') === room_id;
});
}
My reading of the source (DS.Store.find) shows that what you'd actually be receiving in this instance is an AdapterPopulatedModelArray. A FilteredModelArray would auto-update as you create records. There are passing tests for this behaviour.
As of ember.data 1.13 store.filter was marked for removal, see the following ember blog post.
The feature was made available as a mixin. The GitHub page contains the following note
We recommend that you refactor away from using this addon. Below is a short guide for the three filter use scenarios and how to best refactor each.
Why? Simply put, it's far more performant (and not a memory leak) for you to manage filtering yourself via a specialized computed property tailored specifically for your needs
I'm having difficulty wrapping my head around the following:
There's a view that displays the list of items
I take the list of items from the backend via RESTful interface in JSON using ember-data and hand-crafted adapter
In my view I do something like this:
{{#collection contentBinding="App.recentAdditionsController"}}
...
{{/collection}}
App.recentAdditionsController is defined like this:
App.recentAdditionsController = Em.ArrayController.create({
refresh: function(query) {
var items = App.store.findAll(App.Item);
this.set('content', items);
}
});
And... this doesn't work. The reason being App.store.findAll() returning ModelArray which is much like ArrayController itself.
I saw people doing something like this:
App.recentAdditions = App.store.findAll(App.Item);
I could imagine doing it like that, but how would I refresh the list at will (checking if there's anything new).
Hope all is clear more or less.
I've verified that you can use a ModelArray inside an ArrayController. Here's a jsFiddle example: http://jsfiddle.net/ebryn/VkKX2/
"Now the question is how to make the list update itself if there are new objects in the backend?"
Use App.Model.filter to keep your recordArray in sync. Add the query hash when the filter is invoked to ensure than an initial query was made.
model: ->
App.Model.filter {page: 1}, (data) ->
data
edit: Just saw how old the question was, but leaving it here in case it helps someone.