Event binding with views and AJAX-loaded collections - javascript

I'm starting out with Backbone.JS, and have a question about how this should work.
I have a page which should load a list of sports, and then render the view. Now, because the list of sports is loaded via AJAX, I need to bind events to the collection so that it's only rendered when the data from that collection is actually loaded.
Here's what I've got so far:
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>Test</title>
<script src="../../src/vendor/zepto.js" type="text/javascript" charset="utf-8"></script>
<script src="../../src/vendor/underscore.js" type="text/javascript" charset="utf-8"></script>
<script src="../../src/vendor/backbone.js" type="text/javascript" charset="utf-8"></script>
</head>
<body>
<div id="sportsList"></div>
<script type="text/template" id="sports-template">
<ul>
<% _.each(sports, function(sport){ %>
<li>
<%= sport.getDescription() %>
</li>
<% }); %>
</ul>
</script>
<script type="text/javascript" charset="utf-8" src="application.js"></script>
</body>
</html>
As for the javascript code:
var Sport = Backbone.Model.extend({
getDescription: function() {
return this.get('description');
}
});
var Sports = Backbone.Collection.extend({
model: Sport,
initialize: function(options) {
this.bind("refresh", function() {
options.view.render();
});
var sports = this;
$.ajax({
url: 'http://localhost:8080/?service=ListSportsService&callback=?',
dataType: 'jsonp',
success: function(data) {
sports.refresh(data);
}
});
}
});
var SportsView = Backbone.View.extend({
el: '#sportsList',
template: _.template($('#sports-template').html()),
initialize: function() {
this.model = new Sports({view: this});
},
render: function() {
$(this.el).html(this.template({sports: this.model.models}));
return this;
}
});
var SportsController = Backbone.Controller.extend({
routes: {
'sports': 'listSports'
},
listSports: function() {
new SportsView();
}
});
$(document).ready(function(){
window.app = new SportsController();
Backbone.history.start();
});
The part that really nags me is having to pass the view to the collection and binding the refresh event there so that I can render the view once everything is loaded.
My question is, is there a DRYer/simpler way of doing this that I'm missing?
Keep in mind I'm using ZeptoJS instead of jQuery.

Your collection should read
var Sports = Backbone.Collection.extend({
model: Sport,
url: '/?service=ListSportsService&callback=?'
});
Always use Backbone.sync functionality when possible (here by specifying the url on the collection and using fetch).
Your controller should read
var SportsController = Backbone.Controller.extend({
routes: {
'sports': 'listSports'
},
listSports: function() {
//create the view with the collection as a model
this.sports = new Sports();
this.view = new SportsView({model: this.sports});
this.sports.bind("refresh", this.view.render);
// fetch all the sports
this.sports.fetch();
}
});
Enjoy.

Related

Backbone.js primer customisation issues

I've been trying to get my first Backbone.js app up and running, following the Backbone.js primer here.
I've followed the example through and now I'm trying to customise it for my purposes which are to simply retrieve and read a JSON file from my server. I don't need to be able to change or delete any of the data.
I've set up my html as per the primer below:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Backbone.js Primer</title>
<script type="text/javascript" src="./node_modules/jquery/dist/jquery.min.js"></script>
<script type="text/javascript" src="./node_modules/underscore/underscore-min.js"></script>
<script type="text/javascript" src="./node_modules/backbone/backbone-min.js"></script>
<script type="text/javascript" src="./node_modules/moment/moment.js"></script>
<script type="text/javascript" src="./backbone.js"></script>
</head>
<body>
<div>
<h1>Transcripts Data</h1>
<div id="dailyTranscripts-app">
<ul class="dailyTranscripts-list"></ul>
</div>
</div>
</body>
</html>
I've then coded my backbone.js file as the primer describes below:
var yesterday = moment (new Date()).add(-1, 'days').format('YYYY-MM-DD')
var yesterdaysDataURL = 'https://mihndbotblob.blob.core.windows.net/mihndbot-transcripts/finalTranscripts/dailyTranscripts/' + yesterday + '.json'
// Model class for each transcript iten
var DailyTranscriptsModel = Backbone.Model.extend({
defaults: {
type: null,
MessageID: null,
MessageTime: null,
MessageChannel: null,
MessageSenderID: null,
MessageSenderName: null,
ConversationID: null,
MessageText: null,
MessageRecipientID: null,
QuickReplyDisplayText: null,
QuickReplyPayload: null,
Question: null,
Answer: null,
FollowUpPrompts: null
}
});
// Collection class for the DailyTransctipts list endpoint
var DailyTranscriptsCollection = Backbone.Collection.extend({
model: DailyTranscriptsModel,
url: yesterdaysDataURL
});
// View class for displaying each dailyTranscripts list item
var DailyTranscriptsListItemView = Backbone.View.extend({
tagName: 'li',
className: 'dailyTranscripts',
initialize: function () {
this.listenTo(this.model)
},
render: function () {
var html = '<b>Message ID: </b> ' + this.model.get('MessageID');
html += '<br><b>Message Time: </b>' + this.model.get('MessageTime');
this.$el.html(html);
return this;
}
});
// View class for rendering the list of all dailyTranscripts
var DailyTranscriptsListView = Backbone.View.extend({
el: '#dailyTranscripts-app',
initialize: function () {
this.listenTo(this.collection, 'sync', this.render);
},
render: function () {
var $list = this.$('ul.dailyTranscripts-list').empty();
this.collection.each(function (model) {
var item = new DailyTranscriptsListItemView({model: model});
$list.append(item.render().$el);
}, this);
return this;
}
});
// Create a new list collection, a list view, and then fetch list data:
var dailyTranscriptsList = new DailyTranscriptsCollection();
var dailyTranscriptsView = new DailyTranscriptsListView({collection: dailyTranscriptsList });
dailyTranscriptsList.fetch();
The major changes I've made to the code (apart from some customisations) are to remove the templates the primer uses to create the views (I couldn't get them working) and I've removed the Backbone CRUD elements as I only require my app to read data from the server, not update or delete it.
The issue I have is that whilst I'm pulling back the JSON file from the server, none of the data is rendering in the HTLM <div> as expected, it's just blank.
I know that Backbone.js is retrieving the data as when I add .then(function() {console.log(dailyTranscriptsList);}); to the final dailyTranscriptsList.fetch() call I can see the data in the browser console:
You need to wrap all of your backbone.js code within jQuery's .ready()
// backbone.js
$(document).ready(function () {
// all your backbone.js code here
})
This causes your js to run after the DOM is ready, so Backbone will know how to find the elements it needs in order for views to work.
You could also move <script type="text/javascript" src="./backbone.js"></script> to the end of the page, right before </body>

How to fetch data from Backbone collection to Template

i am just writing a simple backbone program. But i am not getting how to fetch data from backbone collection to backbone template. Complete code is written below:
<!doctype html>
<html>
<head>
<title>Backbone tutorial</title>
</head>
<body>
<div class="user">user</div>
<div class="page"></div>
<script type="text/template" id="user-list-template">
I am not able to get data on daya.key
<h1> <%= data.key %> </h1>
</script>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="underscore.js"></script>
<script type="text/javascript" src="backbone.js"></script>
<script>
This is my Collection code
var Album = Backbone.Collection.extend({
url : "/data.json"
});
This is my view code
var UserList= Backbone.View.extend({
el:'.page',
template:_.template($('#user-list-template').html()),
render : function(){
var that=this;
var album= new Album();
album.fetch({
success:function(album){
var _data = {data : album.models} ;
$(that.el).html(that.template(_data));
}
})
}
});
This is my Router code
var Router = Backbone.Router.extend({
routes: {
"": "home" // #help
}
});
var userList= new UserList();
var router = new Router();
router.on('route:home', function(){
userList.render();
});
Backbone.history.start();
</script>
</body>
</html>
and here is the data.json file
{ "key" : "value to print on template "}
Two modifications i would suggest
1.First check the data feild in your template. Since you are fetching data from the collection it will be array of models.
<h1> <%= data[0].key %> </h1>
or you can use a for loop iterating over the collections
2.The data.json file should look like this
[{"key" : "value"}]
Server needs to return a JSON array of model object for collection.fetch() request. So the data.json should look like this:
[{"key":"value to print on template"},{"key":"another value"}]
And try this collection view render implementation:
Model:
var User = new Backbone.Model.extend({});
Collection:
var Album = new Backbone.Collection.extend({
model: User,
url: "/data.json"
});
//create collection instance
var album = new Album();
View:
var UserList= Backbone.View.extend({
el:'.page',
template:_.template($('#user-list-template').html()),
initialize: function(){
//register a collection data add event handler
this.listenTo(album,"add",this.addUser);
//register a collection data remove event handler
this.listenTo(album,"remove",this.removeUser);
album.fetch();
},
render : function(){
},
addUser: function(user){ //apply model data to view template and append to view element
this.$el.append(this.template(user.toJSON()));
},
removeUser: function(user){
//view state update implementation when data have been removed from collection
}
});
Template:
<script type="text/template" id="user-list-template">
<h1><%= key %></h1>
</script>
div.user view will add/remove user-list view dynamically according to collection data manipulation.
Hope this helpful.

Backbonejs not showing this.options parsed from router

for some reason itemDetails is not parsing the .options in the MenuItemDetails view.
This is the javascript code:
// ROUTER
var AppRouter = Backbone.Router.extend({
routes: {
"": "list",
"menu-items/new": "itemForm",
"menu-items/:item": "itemDetails"
},
list: function(){
$('#app').html('List screen');
},
itemDetails: function(item){
var view = new MenuItemDetails (
{
name: item,
category: 'Entree',
imagepath: 'no-image.jpg'
}
);
$('#app').html(view.render().el);
},
itemForm: function(){
$('#app').html('New item form');
}
});
// VIEWS
var MenuItemDetails = Backbone.View.extend({
render: function(){
var markup = '<div>' +
'<h1>'+this.options.name+'</h1>' +
'</div>';
this.$el.html(markup);
return this;
}
});
var app = new AppRouter();
$(function() {
Backbone.history.start();
});
The html code is:
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Test</title>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script src="http://jashkenas.github.io/underscore/underscore-min.js"></script>
<script src="http://jashkenas.github.io/backbone/backbone-min.js"></script>
<script src="http://getbootstrap.com/dist/js/bootstrap.js"></script>
<script src="js/views/menuitemdetails.js"></script>
<script src="js/app.js"></script>
<link href="http://getbootstrap.com/dist/css/bootstrap.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div class="container">
<h1>Off the Backbone</h1>
<ul class="nav nav-pills">
<li>Food</li>
<li>Add Item</li>
<li>Garden Salad</li>
</ul>
<div class="container" id="app">
</div>
</div>
</body>
</html>
As you can see, the two first links are doing well but the third one is getting an error which tells that the parameters in itemDetails are not parsed to the view. Please help me with this one here.
Your router works fine. It's the way in which your passing the data from the router into the view that's broken. Here is a working jsfiddle: http://jsfiddle.net/somethingkindawierd/rEa88/
Relevant changes are defining the model
var MenuItemModel = Backbone.Model.extend();
and then passing it into the view
var view = new MenuItemDetails ({
model: new MenuItemModel({
name: item,
category: 'Entree',
imagepath: 'no-image.jpg'
})
});
then using the model when rendering
'<h1>'+this.model.get('name')+'</h1>'
Your router seems confusing :
"menu-items/new": "itemForm",
"menu-items/:item": "itemDetails"
According to this mapping, both of the following will link will map to the itemDetails method :
<li>Add Item</li>
<li>Garden Salad</li>
The correct way is to change your router to handle only one route like so :
"menu-items/:item": "wrapper"
and handle the logic correctly in wrapper :
wrapper: function(item){
if(item === 'new'){
//handle new
} else {
//handle everything else
}
HTH!

backbone collection. fetch() not rendering the view in mozilla

i am trying to learn backbone.js ( Backbone.js 1.0.0) this is my sample html page where iam using collection. fetch() method to get the collection,and it is displayed using view .i am getting result in
google chrome,but nothing is displayed in mozilla. i don't know the exact reason.
while i refere to backone site http://backbonejs.org/#Collection-fetch
it is qouted that :
Note that fetch should not be used to populate collections on page load — all models needed at load time should already be bootstrapped in to place. fetch is intended for lazily-loading models for interfaces that are not needed immediately: for example, documents with collections of notes that may be toggled open and closed.
is this is related with my issue?
this is my sample html page
<!DOCTYPE html>
<html>
<head>
<title>Backbone Application</title>
<script src="js/jquery.js" type="text/javascript"></script>
<script src="js/underscore.js" type="text/javascript"></script>
<script src="js/backbone.js" type="text/javascript"></script>
</head>
<body>
<div class="list"></div>
<script id="personTemplate" type="text/template">
<td> <strong><%= name %></strong></td>
<td>(<%= age %>) </td>
<td> <%= occupation %> </td>
</script>
<script type="text/javascript">
//Person Model
var Person = Backbone.Model.extend({
defaults: {
name: 'Guest User',
age: 30,
occupation: 'worker'
}
});
// A List of People
var PeopleCollection = Backbone.Collection.extend({
model: Person,
initialize: function(){
alert("intialise")
},
url:'/RestFul/rest/members/info',
});
// View for all people
var PeopleView = Backbone.View.extend({
tagName: 'table',
render: function(){
this.collection.each(function(person){
var personView = new PersonView({ model: person });
this.$el.append(personView.render().el); // calling render method manually..
}, this);
return this; // returning this for chaining..
}
});
// The View for a Person
var PersonView = Backbone.View.extend({
tagName: 'tr',
template: _.template($('#personTemplate').html()),
////////// initialize function is gone from there. So we need to call render method manually now..
render: function(){
this.$el.html( this.template(this.model.toJSON()));
return this; // returning this from render method..
}
});
var peopleCollection = new PeopleCollection();
//peopleCollection.fetch();
peopleCollection.fetch({ success: function () { console.log("collection fetched"); } });
//peopleCollection.fetch({context:collection}).done(function() {
// console.log(this.length)
// })
//console.log(peopleCollection.toJSON())
alert(JSON.stringify(peopleCollection));
var peopleView = new PeopleView({ collection: peopleCollection });
$(document.body).append(peopleView.render().el); // adding people view in DOM
</script>
</body>
</html>
any help will be appreciated
Try with
var fetching = peopleCollection.fetch({ success: function () { console.log("collection fetched"); } });
$.when(fetching).done(function(){
var peopleView = new PeopleView({ collection: peopleCollection });
$(document.body).append(peopleView.render().el); // adding people view in DOM
});
var fetching = peopleCollection.fetch({ success: function () {
var peopleView = new PeopleView({ collection: peopleCollection });
$(document.body).append(peopleView.render().el);
} });
I think we can call the view render inside the success callback

Simplest of backbone.js examples

I'm creating a bare bones backbone example to try to learn it and am having issues getting my view to render. I've based it on Thomas Davis's tutorial but looked at many of the other apps and tutorials available.
I'm changing Davis's tutorial not only because I want to add an input box, but also because based on the backbone docs I thought it needed less code and a different structure. Obviously because I can't get this to work, I don't know what's needed and what isn't.
My ultimate goal was to just add the names in li tags within ul#friends-list, although I don't think el: 'body' will help me there.
What am I doing wrong? Thanks for any help.
My html:
<!DOCTYPE HTML>
<html>
<head>
<title>Tut</title>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js"></script>
<script type="text/javascript" src="http://ajax.cdnjs.com/ajax/libs/underscore.js/1.1.4/underscore-min.js"></script>
<script type="text/javascript" src="http://ajax.cdnjs.com/ajax/libs/backbone.js/0.3.3/backbone-min.js"></script>
</head>
<body>
<input type="text" placeholder="Enter friend's name" id="input" />
<button id="add-input">Add Friend</button>
<ul id="friends-list">
</ul>
<script type="text/javascript" src="test.js"></script>
</body>
</html>
My test.js
$(function() {
Friend = Backbone.Model.extend();
//Create my model
var friends = new Friend([ {name: 'Eddard Stark'}, {name: 'Robert Baratheon'} ]);
//Create new models to be used as examples
FriendList = Backbone.Collection.extend({
model: Friend
});
//Create my collection
var friendslist = new FriendList;
//Created to hold my friends model
FriendView = Backbone.View.extend({
tagName: 'li',
events: {
'click #add-input': 'getFriend',
},
initialize: function() {
_.bindAll(this, 'render');
},
getFriend: function() {
var friend_name = $('#input').val();
var friend_model = new Friend({name: friend_name});
},
render: function() {
console.log('rendered')
},
});
var view = new FriendView({el: 'body'});
});
You had some fundamental problems with your code to get the functionality that you required. I turned your code into a jsfiddle and you can see the working solution here.
http://jsfiddle.net/thomas/Yqk5A/
Code
<!DOCTYPE HTML>
<html>
<head>
<title>Tut</title>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js"></script>
<script type="text/javascript" src="http://ajax.cdnjs.com/ajax/libs/underscore.js/1.1.4/underscore-min.js"></script>
<script type="text/javascript" src="http://ajax.cdnjs.com/ajax/libs/backbone.js/0.3.3/backbone-min.js"></script>
</head>
<body>
<input type="text" placeholder="Enter friend's name" id="input" />
<button id="add-input">Add Friend</button>
<ul id="friends-list">
</ul>
<script type="text/javascript" src="test.js"></script>
</body>
</html>
$(function() {
FriendList = Backbone.Collection.extend({
initialize: function(){
}
});
FriendView = Backbone.View.extend({
tagName: 'li',
events: {
'click #add-input': 'getFriend',
},
initialize: function() {
var thisView = this;
this.friendslist = new FriendList;
_.bindAll(this, 'render');
this.friendslist.bind("add", function( model ){
alert("hey");
thisView.render( model );
})
},
getFriend: function() {
var friend_name = $('#input').val();
this.friendslist.add( {name: friend_name} );
},
render: function( model ) {
$("#friends-list").append("<li>"+ model.get("name")+"</li>");
console.log('rendered')
},
});
var view = new FriendView({el: 'body'});
});
I noticed that you wanted as little code as possible so I left some things out that you don't need such as declaring an actual model. It might be easier if you use a collection like in the example instead.
Also I have just launched a new site containing Backbone tutorials which might help solve your problem.
BackboneTutorials.com

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