Backbone.js iterating through JSON results from fetch() - backbone.js

I am very new to Backbone and just trying to figure out the way things work. How do I iterate through the "fetched" results?
(function($) {
console.log('Formcontainer init.');
var Field = Backbone.Model.extend({
defaults: {
id: "0",
memberlist_id: "3",
field_name: "sample-field-name",
},
initialize: function() {
console.log('Field model init.');
}
});
var FieldCollection = Backbone.Collection.extend({
defaults: {
model: Field
},
model: Field,
url: 'http://localhost:8888/getstuff/3.json',
initialize: function() {
console.log('FieldCollection init.');
}
});
var ListView = Backbone.View.extend({
el: '#app-container',
initialize: function() {
_.bindAll(this,"render");
console.log('ListView init.')
this.counter = 0;
this.collection = new FieldCollection();
this.collection.fetch();
//this.collection.bind('reset', function() { console.log('xxx')});
//this.collection.fetch();
this.render();
},
events: {
'click #add': 'addItem'
},
render: function() {
var self = this;
console.log('Render called.');
},
addItem: function() {
this.counter++;
this.$("ul").append("<li>hello world" + this.counter + "</li>");
}
});
var listView = new ListView();
})(jQuery);
I get this in my Firebug console:
Formcontainer init.
ListView init.
FieldCollection init.
GET http://localhost:8888/getstuff/3.json 200 OK
Render called.
Field model init.
Field model init.
Field model init.
Field model init.
Field model init.
It seems that the fetch() was called - since "Field model init." is in the console 5 times. But how to I output that? I would want to append the items in an unordered list.
Thanks!

Bind the reset event to your render function...
this.collection.bind('reset', this.render, this);
This gets triggered after the fetch is complete, so you can create the list...
render: function() {
var self = this;
console.log('Render called.');
this.collection.each(function(i,item) {
this.$el.append("<ul>" + item.get("field_name") + "</ul>");
});
},

Related

Backbone.js collection view render multiple times for single trigger

I have backbone.js collection and collectionview. collection view listening to its collection add event. But when I add new models to it's collection it renders mutiple times for each model.
Please Check the JSFiddle
var ImageCollectioView = Backbone.View.extend({
initialize: function() {
this.collection.bind('add', this.render, this);
},
collection: imgColection,
el: '#cont',
render: function() {
var els = [], self = this;
this.collection.each(function(image){
var imageView = new ImageView({model: image});
self.$el.append(imageView.render().el);
});
return this;
}
});
Your render method renders the entire collection. So after adding a model you should clear the existing item views:
render: function() {
var els = [], self = this;
this.$el.empty();
//------^---- clear existing
this.collection.each(function(image){
var imageView = new ImageView({model: image});
self.$el.append(imageView.render().el);
});
return this;
}
That being said, it's better to add a separate method that just appends single item view rather than rendering the entire collection:
var ImageCollectioView = Backbone.View.extend({
initialize: function() {
this.render();
this.listenTo(this.collection, 'add', this.renderItem);
},
el: '#cont',
render: function() {
this.collection.each(this.renderItem, this);
return this;
},
renderItem: function(image) {
var imageView = new ImageView({
model: image
});
this.$el.append(imageView.el);
}
});
Updated Fiddle

How to filter a backbone collection and render the results

Total newbie to Backbone so apologize if this is a simple question.
I am have successfully loaded a collection and rendered the view. However I have a dropdown with A tags that I would like to use the filter the data displayed. I'm trying to set an event listener in my VIEW and then trigger a function within the view to filter the results and re-render the view.
Here's my code:
IBA.NewsModel = Backbone.Model.extend({});
IBA.NewsCollection = Backbone.Collection.extend({
model: IBA.NewsModel,
url: "/news/api"
});
IBA.NewsView = Backbone.View.extend({
el: '#main',
template: _.template($("#news-article").html()),
events: {
"change .dropdown-item": "filterNews"
},
initialize: function () {
this.collection = new IBA.NewsCollection();
this.listenTo(this.collection, 'reset', this.render);
this.collection.fetch({
success: function() {
console.log("JSON file load was successful");
view.render();
},
error: function(){
console.log('There was some error in loading and processing the JSON file');
}
});
},
render: function () {
this.$el.html(this.template({
articles: this.collection.toJSON()
})
);
return this;
},
filterNews: function (e){
e.preventDefault();
var items = this.collection.where({cat_name: "interviews"});
console.log(items);
this.$el.html(this.template({articles: this.items.toJSON()}));
}
});
var view = new IBA.NewsView();
Easiest way to do it would be to reset the actual collection with the filtered results:
IBA.NewsModel = Backbone.Model.extend({});
IBA.NewsCollection = Backbone.Collection.extend({
model: IBA.NewsModel,
url: "/news/api"
});
IBA.NewsView = Backbone.View.extend({
el: '#main',
template: _.template($("#news-article").html()),
events: {
"change .dropdown-item": "filterNews"
},
initialize: function() {
this.collection = new IBA.NewsCollection();
this.listenTo(this.collection, 'reset', this.render);
this.fetchNews();
},
fetchNews: function() {
var view = this;
this.collection.fetch({
success: function() {
console.log("JSON file load was successful");
view.render();
},
error: function() {
console.log('There was some error in loading and processing the JSON file');
}
});
},
render: function() {
this.$el.html(this.template({
articles: this.collection.toJSON()
}));
return this;
},
filterNews: function(e) {
e.preventDefault();
this.collection.reset(this.collection.where({
cat_name: "interviews"
}));
}
});
var view = new IBA.NewsView();
When you want to go back to original data, fetch it again using the fetchNews() method.
You also had a syntax error that view was not defined in your initialize

backbone fetch collection on infinite scroll

I'm learning backbone and now thinking of how to apply an infinite scroll and fetch/load lets say 20 items from my collection every time the scroll is at the bottom of the page.
I have been searching around a lot after different libs and such without really getting any closer. Anyone that can explain/show how this is best done?
I have now added the infiniscroll.js plugin and trying to get it to work. But on scroll it won't load new items. What am i supposed to do on the appendRender? and how?
var StartView = Backbone.View.extend({
tagName: "section",
id: "start",
className: "content",
events: {
},
initialize: function(){
$(".container").html(this.el);
console.log("init start");
this.template = _.template($("#start_template").html(), {} );
this.collection = new VideoCollection();
_.bindAll(this, "render");
this.render();
this.infiniScroll = new Backbone.InfiniScroll(this.collection, {
success: this.appendRender,
pageSize: this.collection.length,
scrollOffset: 100
});
},
appendRender: function() {
var self = this;
self.$el.html(self.template);
self.$el.find(".videos").append("<div style='margin-bottom:30px; width:100%; height:170px; float:left; background-color:#e4e4e4;'>fff</div>")
},
render: function(){
var self = this;
this.$el.html("loading");
console.log("render start")
},
kill: function() {
console.log("kill start");
this.remove();
}
});
return StartView;
The backbone-pageable plugin supports infinite scrolling.
It's just a matter of your collection extending Backbone.PageableCollection, and you specifying some extra properties. There's also an example of a backbone view listening to the changing collection, as well as fetching on scroll.
It's all described on the github page. It's updated fairly often.
I would have done it something like this (although the document.addEventListener('scroll')-part isn't really elegant
(function() {
"use strict";
var Item = Backbone.Model.extend({});
var Items = Backbone.Collection.extend({
model: Item,
url: "/api/items/"
});
var ItemView = Backbone.View.extend({
tagName: "li",
render: function() {
this.$el.html(this.model.get("name"));
return this;
}
});
var ItemsList = Backbone.View.extend({
tagName: "ul",
offset: 0,
limit: 60,
initialize: function() {
this.collection = new Items();
this.collection.on("reset", this.addAll, this);
this.collection.on("add", this.addOne, this);
this.getItems();
},
render: function () {
return this;
},
getItems: function () {
this.collection.fetch({
"data": {"offset": this.offset, "limit": this.limit},
"success": _.bind(function(e){
this.offset += this.limit;
}, this)
});
},
addOne: function(item) {
var view = new ItemView({model: item});
this.$el.append(view.render().$el);
},
addAll: function() {
this.collection.each(this.addOne, this);
}
});
var itemsList = new ItemsList();
$(document.body).append(itemsList.render().$el);
document.addEventListener('scroll', function (event) {
if (document.body.scrollHeight == document.body.scrollTop + window.innerHeight) {
itemsList.getItems();
}
});
}());

Backbone.js Collections View forEach doesn't work

I am trying to use collections to list my data coming from my api.
But the problem is, when I use forEach, the function that I called (addOne) doesn't run.
There is also something I suspect working wrong. Should my collection save the returning JSON under the models like that?
Object -> models -> 0 -> attributes -> ...
My View:
s.Views.Fs = Backbone.View.extend({
className: "",
template: _.template("<%= name %>"),
initialize: function() {
},
render: function() {
this.collection.forEach(this.addOne, this);
},
addOne: function(f) {
alert("a");
var fV = new s.Views.PF({model: f});
this.$el.append(fV.render().el);
}
});
My Collection:
s.Collections.FL = Backbone.Collection.extend({
url: "api/fs/",
model: s.Models.F,
});
My Model:
s.Models.F = Backbone.Model.extend( {
urlRoot: 'api/fs/',
defaults: {
...
},
...
parse: function(response) {
return response;
},
});
My Route (And App):
var sApp = new (Backbone.Router.extend({
f_a: function() {
this.fL= new s.Collections.FL();
this.fLV= new s.Views.Fs({collection: this.fL});
this.fL.fetch();
this.fLV.render();
},
});
Listening for events is made by this.collection.on('add', this.addOne, this); under collection's view. Here is tested code's summary (Thanks for the tip 'mu is too short'):
VIEW
s.Views.Fs = Backbone.View.extend({
className: "",
template: _.template("<%= name %>"),
initialize: function() {
this.collection.on('add', this.addOne, this);
this.collection.on('reset', this.render, this);
},
render: function() {
this.collection.forEach(this.addOne, this);
},
addOne: function(f) {
var fV = new s.Views.PF({model: f});
fV.render();
this.$el.append(fV.el);
}
});
COLLECTION
s.Collections.FL = Backbone.Collection.extend({
url: "api/fs/",
model: s.Models.F,
});
MODEL
s.Models.F = Backbone.Model.extend( {
urlRoot: 'api/fs/',
// No need to parse here.
});
ROUTER
var sApp = new (Backbone.Router.extend({
f_a: function() {
this.fL= new s.Collections.FL();
this.fLV= new s.Views.Fs({collection: this.fL});
this.fLV.render();
$("#content").html(this.fLV.el);
this.fL.fetch();
},
});

Calling destroy on collection

I am doing a sample application similar to the Backbone-Todo. But when I am invoking destroy on collection it's giving error:
Uncaught TypeError: Cannot read property 'destroy' of undefined
How can I solve this problem. Please suggest.
Following is my method code:
$(function(){
var Todo = Backbone.Model.extend({
defaults: function() {
return {
title: "empty todo...",
order: Todos.nextOrder(),
done: false
};
}
});
var TodoList = Backbone.Collection.extend({
model : Todo,
localStorage: new Backbone.LocalStorage("todos-backbone"),
done: function() {
return this.where({done: true});
},
remaining: function() {
return this.without.apply(this, this.done());
},
nextOrder: function() {
if (!this.length) return 1;
return this.last().get('order') + 1;
},
comparator: 'order'
});
var TodoView = Backbone.View.extend({
tagName: "li",
template: _.template($('#item-template').html()),
events: {
"click a.destroy" : "clear"
},
initialize: function() {
this.listenTo(this.model, 'destroy', this.remove);
},
render: function() {
this.$el.html(this.template(this.model.toJSON()));
return this;
},
clear: function(){
this.model.destroy();
}
});
var AppView = Backbone.View.extend({
el: $("#todoapp"),
statsTemplate: _.template($('#stats-template').html()),
events: {
"keypress #new-todo": "createOnEnter",
"click #remove-all": "clearCompleted"
},
initialize: function() {
this.input = this.$("#new-todo");
this.main = $('#main');
this.footer = this.$('footer');
this.listenTo(Todos, 'add', this.addOne);
this.listenTo(Todos, 'all', this.render);
Todos.fetch();
},
render: function() {
var done = Todos.done().length;
var remaining = Todos.remaining().length;
if (Todos.length) {
this.main.show();
this.footer.show();
this.footer.html(this.statsTemplate({done: done, remaining: remaining}));
} else {
this.main.hide();
this.footer.hide();
}
},
createOnEnter: function(e){
if(e.keyCode != 13) return;
if (!this.input.val()) return;
Todos.create({
title: this.input.val()
})
this.input.val('');
},
addOne: function(todo){
var view = new TodoView({model: todo});
this.$("#todo-list").append(view.render().el);
},
clearCompleted: function(){
_.invoke(Todos, 'destroy');
return false;
}
});
for this answer I assume Todos is an instance of TodoList. I also assume that your error is fired by this function in your AppView
clearCompleted: function(){
_.invoke(Todos, 'destroy');
return false;
}
In there you're trying to treat your Backbone.js Collection instance like what it is, a collection eg a list. But Backbone collections are not simply lists, they are objects that have the property models which is a list that contains all your models. So trying to use underscore's invoke (which works on lists) on an object is bound to cause errors.
But don't worry, Backbone neatly implements many Underscore methods for its Model and Collection, including invoke. This means you can invoke destroy for each model in a collection like this
SomeCollection.invoke('destroy');
Hope this helps!

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