Below I have the code for one of my modules. This is kind of spagetti-ish code, but all I want to accomplish is having a model, a collection, and render a view (using underscore templates) connecting the data from the collection to the views. I'm failing miserably. The problem I'm getting is that trying to run the last call down there to testfeed.render() tells me that render is not a function, yet it is clearly defined. I'm able to fetch that data and seemingly add it to the collection from the api. What am I doing wrong here?
// Create a new module.
var Tagfeed = app.module();
// Default model.
Tagfeed.Model = Backbone.Model.extend({
defaults : {
name : '',
image : ''
},
initialize : function(){
console.log('tagfeed model is initialized');
this.on("change", function(){
console.log("An attribute has been changed");
});
}
});
var feedCollection = Backbone.Collection.extend({
model: Tagfeed.Model,
initialize : function () {
console.log('feedcollection is initialized');
},
fetch: function () {
var thisCollection = this;
Api_get('/api/test', function(data){
$.each(data.data, function(){
thisCollection.add(this);
});
return thisCollection;
})
}
});
var test = new Tagfeed.Model({name:'test'});
var newFeedCollection = new feedCollection();
newFeedCollection.fetch();
console.log(newFeedCollection.at(0));
var testfeed = Backbone.View.extend({
el: $('#main'),
collection : newFeedCollection,
render: function( event ){
var compiled_template = _.template( $("#tag-template").html() );
this.$el.html( compiled_template(this.model.toJSON()) );
return this; //recommended as this enables calls to be chained.
}
});
testfeed.render();
EDIT * updated code from #mu is short suggestions
// Create a new module.
var Tagfeed = app.module();
// Default model.
var tagModel = Backbone.Model.extend({
defaults : {
name : '',
image : '',
pins : 0,
repins : 0,
impressions : 0
},
initialize : function(){
console.log('tagfeed model is initialized');
this.on("change", function(){
console.log("An attribute has been changed");
});
}
});
var feedCollection = Backbone.Collection.extend({
model: tagModel,
initialize : function () {
console.log('feedcollection is initialized');
},
fetch: function () {
var thisCollection = this;
Api_get('/reporting/adlift/pin_details', function(data){
thisCollection.add(data.data);
return data.data;
})
}
});
var test = new tagModel({name:'test'});
var newFeedCollection = new feedCollection();
newFeedCollection.fetch();
console.log(newFeedCollection.at(0));
var TestFeed = Backbone.View.extend({
el: $('#main'),
render: function( event ){
console.log('here');
var compiled_template = _.template( $("#tag-template").html(), this.collection.toJSON());
this.el.html( compiled_template );
return this; //recommended as this enables calls to be chained.
},
initialize: function() {
console.log('initialize view');
this.collection.on('reset', this.render, this);
}
});
//Tagfeed.testfeed.prototype.render();
var testfeed = new TestFeed({ collection: newFeedCollection });
testfeed.render();
and now when i run testfeed.render() I don't see any error, nor do i see that console.log in the render function. thoughts?
Your problem is right here:
var testfeed = Backbone.View.extend({ /*...*/ });
testfeed.render();
That makes your testfeed a view "class", you have to create a new instance with new before you can render it:
var TestFeed = Backbone.View.extend({ /*...*/ });
var testfeed = new TestFeed();
testfeed.render();
You're also doing this inside the "class":
collection : newFeedCollection
That will attach newFeedCollection to each instance of that view and that might cause some surprising behavior. The usual way of getting a collection into a view is pass it to the constructor:
var TestFeed = Backbone.View.extend({ /* As usual but not collection in here... */ });
var testfeed = new TestFeed({ collection: newFeedCollection });
testfeed.render();
The view constructor will automatically set the view's this.collection to the collection you pass when building the view.
Another thing to consider is that this:
newFeedCollection.fetch();
is usually an AJAX call so you might not have anything in your collection when you try to render it. I would do two things to deal with this:
Your view's render should be able to deal with an empty collection. This mostly depends on your template being smart enough to be sensible when the collection is empty.
Bind render to the collection's "reset" event in the view's initialize:
initialize: function() {
this.collection.on('reset', this.render, this);
}
Another problem you'll have is that your view's render is trying to render this.model:
this.$el.html( compiled_template(this.model.toJSON()) );
when your view is based on a collection; you want to change that to:
this.$el.html(compiled_template({ tags: this.collection.toJSON() }));
You'll need the tags in there so that the template has a name to refer to when looking at the collection data.
Also, you should be able to replace this:
$.each(data.data, function(){
thisCollection.add(this);
});
with just this:
thisCollection.add(data.data);
There's no need to add them one by one, Collection#add is perfectly happy with an array of models.
And here's a demo with (hopefully) everything sorted out:
http://jsfiddle.net/ambiguous/WXddy/
I had to fake the fetch internals but everything else should be there.
testfeed is not an instance - it's a constructor function.
var instance = new testfeed();
instance.render();
would probably work (what with you defining el during View definition - making it a prototype property, IIRC).
Related
I have a Backbone collection which I am fetching and rendering the following way:
var View = Backbone.View.extend({
initialize : function(options){
var self = this;
this.template = _.template(Index);
this.collection = new WineCollection();
this.collection.url = ApiConfig.winetards.getWineList;
this.collection.on("reset", function(){self.render()});
return this;
}
At somepoint the wineList collection will be empty. How can I trigger "reset" and then call render on when the result set is empty?
You have two options - write the logic in View or the Collection. If other parts of your application will care when the collection is empty, do it in the Collection. Otherwise it probably belongs in the View.
Unless you edit the Collection's models Array directly, the Collection can only become empty after a reset or remove event. You can listen to these events and check for an empty Collection.
In the view
var View = Backbone.View.extend({
initialize : function(options){
this.listenTo(this.collection, 'remove reset', this.renderIfEmpty, this);
},
renderIfEmpty: function() {
if(this.collection.isEmpty()) {
this.render();
}
}
}
In the collection
var WineList = Backbone.Collection.extend({
initialize: function() {
this.on('remove reset', this.checkEmpty);
// If you want to trigger an event when an empty collection is created:
this.checkEmpty();
},
checkEmpty: function() {
if(this.isEmpty()) {
this.trigger('emptied', this)
}
}
})
I am using a collection view to render my array of model views. I have added a method that removes a single model view from the existing collection view, and attempts to re-render it in a new el: element.
I use collection.get(this.model) to save the model to a variable, I add that variable to my new collection which is the model of a new collection view associated with a new DOM element, and I re-use the same collection view render method. When I console.log() the new collection, I see the model that I picked from the old collection, but it's not rendering on the page.
<script>
(function($){
//---------SINGLE ENTRY MODEL----------
var Entry = Backbone.Model.extend({
defaults: function(){
return{
word: '',
definition: ''
}
}
});
//------------ENTRY MODEL COLLECTION------------
var EntryList = Backbone.Collection.extend({
model: Entry
});
//-----INSTANCIATE COLLECTION----
var dictionary = new EntryList();
var saved = new EntryList();
//-----SINGLE ENTRY VIEW------
var EntryView = Backbone.View.extend({
model: new Entry(),
tagName:'div',
events:{
'click .edit': 'edit',
'click .delete': 'delete',
'keypress .definition': 'updateOnEnter',
'click .save': 'save'
},
delete: function(ev){
ev.preventDefault;
dictionary.remove(this.model);
},
edit: function(ev){
ev.preventDefault;
this.$('.definition').attr('contenteditable', true).focus();
},
//method that adds existing model to new collection
save: function(ev){
ev.preventDefault;
var savedEntry = dictionary.get(this.model);
dictionary.remove(this.model);
saved.add(savedEntry);
console.log(savedEntry.toJSON());
},
close: function(){
var definition = this.$('.definition').text();
this.model.set('definition', definition);
this.$('.definition').attr('contenteditable', false).blur();
},
updateOnEnter: function(ev){
if(ev.which == 13){
this.close();
}
},
initialize: function(){
this.template = _.template($("#dictionary_template").html());
},
render: function(){
this.$el.html(this.template(this.model.toJSON()));
return this;
}
});
//--------------DICTIONARY VIEW------------
var DictionaryView = Backbone.View.extend({
model: dictionary,
el: $('#entries'),
initialize: function(){
this.model.on('add', this.render, this);
this.model.on('remove', this.render, this);
},
render: function(){
var self = this;
self.$el.html('');
_.each(this.model.toArray(), function(entry, i){
self.$el.append((new EntryView({model: entry})).render().$el);
});
return this;
}
});
//---------SAVED ENTRY VIEW-----------
var SavedView = Backbone.View.extend({
model: saved,
el: $('#saved'),
initialize: function(){
this.model.on('save', this.savedRender, this);
},
//method that renders new collection view with different el:
savedRender: function(){
var self = this;
self.$el.html('');
_.each(this.model.toArray(), function(saved, i){
self.$el.append((new EntryView({model: savedEntry})).render().$el);
});
return this;
}
});
//-------BINDING DATA ENTRY TO NEW MODEL VIEW-------
$(document).ready(function(){
$('#new-entry').submit(function(ev){
var entry = new Entry({word: $('#word').val(), definition: $('#definition').val() });
dictionary.add(entry);
dictionary.comparator = 'word';
console.log(dictionary.toJSON());
$('.form-group').children('input').val('');
return false;
});
var appView = new DictionaryView();
});
//--------------ROUTER----------------
var Router = Backbone.Router.extend({
routes:{
'':'home'
}
});
var router = new Router();
router.on('route:home', function(){
console.log('router home');
});
Backbone.history.start();
})(jQuery);
</script>
There are a number of problems here.
First, you do not have an instance of SavedView. The var SavedView = Backbone.View.extend(...); statement is just defining the SavedView class. In order to have a living instance of this class, you must initialize one with the new operator. You will need a line like the following somewhere in your code (a good place would be at the end of the jQuery ready handler):
var saved_view = new SavedView();
Next, we will investigate the save method of the EntryView class. The var savedEntry = dictionary.get(this.model); statement is completely unnecessary because we know that dictionary.get(this.model) will return this.model - which we obviously already have an instance of. So we can remove the clutter from this method and be left with the following:
ev.preventDefault;
saved.add(this.model);
dictionary.remove(this.model);
However, we are still not at our destination. If we turn our attention to the SavedView class definition, we see that it is binding its render method to the 'save' event on its collection, the saved object. Its not the 'save' event we should be binding to, but rather the 'add' event - as that is what will be triggered when we add models to saved:
this.model.on('add', this.savedRender, this);
If we test our code now we should get scolded with a reference error on savedEntry within SavedView.savedRender. It looks like this is a typo and what was intended was `saved'. (You will notice below that in addition to correcting the typo, I have also removed a set of parentheses from this expression that served no function save for making the code less readable):
self.$el.append(new EntryView({ model: saved }).render().$el);
EDIT:
In response to your follow-up question about the saved variable inside the SavedView.savedRender method:
The saved object in this case is a single Entry model. The reason for your confusion is that we are re-using the variable name "saved". Within the _.each callback we have defined the first parameter to be called "saved"; this "saved" is local to the callback and is not related to the EntryList collection defined previously. Within our callback, saved is an element of the saved collection (yikes!) - which is a lesson in why variable naming is important.
As I proceeded to change the name of "saved" in the savedRender method, I noticed a few other refactorings that were screaming to be made. I have listed my refactorings below:
A purpose of using Backbone (http://backbonejs.org/) is to give us access to convenient helpers for objects (models) and arrays (collections). Backbone collections have an each method we can make use of instead of passing our collection to Underscore's (http://underscorejs.org/) each.
As stated above, saved is a terrible name for our each callback parameter because it conflicts conceptually with the name of the collection. Because saved is a collection of Entry models, "entry" is a much more suitable name.
Backbone allows us to pass the context to our each callback that will be our this within that callback. This allows us to skip the step of caching our this in the self variable.
My refactored savedRender becomes:
savedRender: function () {
this.$el.empty();
this.model.each(function (entry) {
this.$el.append(new EntryView({ model: entry }).render().$el);
}, this);
return this;
}
Im having trouble with a render function. The function takes an array as parameter an returns new models of the collection. But it only renders once. I run it on a click and the collection itself listen to "change". The problem is that the collection does not get the new items.
I think its the reset function that is the problem. But i don't know how to do it in another way. Basically i just want to remove all previous models and set the new ones. How would i do that?
Thanks!
filter: function(f) {
var filter = this.collection.filter(function(o){
var accept = false;
$(f).each(function(i,val){
if(_.indexOf(o.get('tags'), val) >-1){
accept = true;
}
})
return accept;
});
this.collection.reset(filter);
new PeopleView({
el: this.$('.list'),
collection: this.collection
});
},
PeopleView render:
PeopleView = Backbone.View.extend({
initialize: function () {
this.render();
},
render: function () {
this.$el.html('');
this.collection.each(this.renderPerson, this);
this.listenTo(this.collection,'change',this.render);
},
renderPerson: function (person) {
this.$el.append(new PersonView({
tagName: 'li',
id:'p_'+person.get('id'),
model: person
}).el);
},
});
I made a simpler version of this on code pen and got it working (no view and filters criteria is hard coded) but the principle seems the same
the main difference is that it listens for a "reset" event on my collection seeing as that is what you are asking the collection to do. You can see it here, just have your console open to see the results
var PeopleModel = Backbone.Model.extend({
});
var PeopleCollection = Backbone.Collection.extend({
model: PeopleModel
});
var peopleCollection = new PeopleCollection([{
id: 1,
name: "jim"
}, {
id: 2,
name: "fred"
}]);
//listen for restet
peopleCollection.on("reset", function() {
console.log("people reset");
console.log(peopleCollection.models);
});
var filter = peopleCollection.filter(function(o) {
var accept = false;
$(['i']).each(function(i, val) {
if (_.indexOf(o.get('name'), val) > -1) {
accept = true;
}
});
return accept;
});
console.log("people:",peopleCollection);//this will print that the collection has two models
peopleCollection.reset(filter); //now i have rest with the filter the log will show only one model
If you want to remove set of model from collection try below simple solution
http://backbonejs.org/#Collection-remove
that.collection.remove(filter);
This is my view for a collection
var mssg = mssg || {};
mssg.MessagesView = Backbone.View.extend({
el: '#messages',
initialize: function() {
this.collection.fetch();
this.collection.bind('reset', this.render, this);
},
render : function() {
this.$el.html('');
this.collection.each(function( item ) {
this.renderMessage( item );
}, this );
return this;
},
renderMessage : function( item ) {
var messageView = new mssg.MessageView({
model : item
});
this.$el.append( messageView.render().el );
}
});
this is the collection
var mssg = mssg || {};
mssg.Messages = Backbone.Collection.extend({
model : mssg.Message,
url : 'messages'
});
and this is how it is initialized:
var mssg = mssg || {};
$(function() {
new mssg.MessagesView({
collection : new mssg.Messages()
});
});
The problem is that the render function bound to reset doesn't fire after the ajax fetch request.
If I bind it to add it works.
I tried binding all to a debuggin function and it says that the sync event is called alongside the add for every item.
If you check backbone change log, you'll see that the way fetch is handled changed in 1.0:
Renamed Collection's "update" to set, for parallelism with the similar
model.set(), and contrast with reset. It's now the default updating
mechanism after a fetch. If you'd like to continue using "reset", pass
{reset: true}
So, to trigger a reset event, you now have to use
this.collection.fetch({reset: true})
in backbone 1.0, you have to trigger reset by hand:
youColloection.fetch({reset: true});
I am creating a view in backbone that accepts a collection I want to then render that view then use the collection to append another view to the orginal but I don't know how to reference the original view in the success function of the collection. When I try the following code I get undefined.
new GenreView().render(new PopVideosCollection());
define (['jquery','underscore','backbone'],function($,_,Backbone) {
GenreView = Backbone.View.extend({
tagName:"div",
className:"sect",
template: _.template($("#genreView").html()),
render: function (collection)
{
this.$el.html(this.template);
collection.fetch ({success:function (video)
{
console.log(video.toJSON());
console.log(GenreView.el);
},
});
},
});
return GenreView;
});
You need to get a reference to the instance of GenreView from inside the callback. Something like this should get you there:
var context = this;
collection.fetch ({success:function (video){
console.log(video.toJSON());
console.log(context.el);
}
});
However, you should re-think your approach a little. It would be better to call fetch on your collection, and have the view subscribe the reset event of your collection. Starting with your example code, that would look something like:
var GenreView = Backbone.View.extend({
initialize: function() {
this.listenTo(this.model, "reset", this.appendSubView);
},
render: function() {
this.model.fetch();
},
appendSubView : function(video){
console.log(video.toJSON());
console.log(this.el);
}
});