Updating backbone view when collection change - javascript

When the first page of my Backbone app load I fetch a collection then iterate over it to render the page:
Page Router:
home: function ()
{
new BodyView ({page:'home'});
new HomeView();
new PostView();
postCollection = new PostCol({userId:getId(),start:0,offset:50});
postCollection.fetch();
postView = new Post({collection:postCollection});
},
Post View:
el:'.stream',
initialize: function ()
{
this.collection.on('reset',this.render.bind(this));
this.collection.on ('change',this.render.bind (this));
},
render: function ()
{
this.collection.each (function (model)
{
actor = new Actor ({model:model});
this.$el.append (actor.render().el);
},this);
return this;
},
What I am trying to accomplish now is that when a user save some data in another view it update the Post view. This is what I did but its not working.
Other View:
post = new PostModel ({userid:getId(),post:postText,objectid:0});
post.save({},
{
success: function (response)
{
postCol = new PostCol ({userId:getId(),start:0,offset:50});
postView = new Post ({collection:postCol});
postCol.fetch ().success({change:true});
},
error: function (response)
{
console.log (response);
}
}
);

It looks like you postCollection is global, so you could update the existing model instead of creating a new one.
// find existing model in the collection.
var post = postCollection.get(getId());
// save model with updated info.
post.save({post:postText},
{
success: function (response)
{
// if the save succeeded, the Post view will re-render,
// since you are listening for the 'change' event.
// so here, you don't really need to do anything.
},
error: function (response)
{
console.log (response);
}
);
Instead of this.collection.on ('change',this.render.bind (this)); in the Post view, you could do this in the individual Actor view, so the whole collection does not re-render.
this.model.on ('change',this.render, this); // 'this' as third parameter replaces the `bind`

Related

Backbone js building a collection from the results returned from multiple URL's

I have a model that looks like this:
var BasicModel = Backbone.Model.extend({
defaults: {
a: '',
b: '',
c: '',
d: '',
e: ''
},
idAttribute: "f",
parse: function (data) {
return data;
},
initialize: function () {
console.log('Intialized');
},
constructor: function (attributes, options) {
Backbone.Model.apply(this, arguments);
}
});
Collections like this:
var BasicCollection = Backbone.Collection.extend({
model: BasicModel,
url: urlCode
});
var ACollection = BasicCollection.extend({
parse: function (data) {
return data.a.b.c.d;
}
});
var aCollection = new ACollection ();
And Views like this:
var BasicView = Backbone.View.extend({
tagName: 'tr',
template: _.template($('#basic-status-template').html()),
render: function () {
this.$el.html(this.template(this.model.attributes));
return this;
}
});
var BasicsView = Backbone.View.extend({
initialize: function () {
this.render();
},
});
This is how the collection fetch looks (Which builds the views):
aCollection.fetch({
success: function () {
// View
var aView = BasicsView.extend({
el: '#foobar #table-body',
render: function () {
this.$el.html('');
aCollection.each(function (model) {
var x = new BasicView({
model: model
});
this.$el.append(x.render().el);
}.bind(this));
return this;
}
});
var app = new aView();
}
});
But now I face a problem when trying to add another piece of detail to the tables that the views will populate. One of the columns will require data that will come from a seperate url. But I still want it to be part of the same process.
Is there are way to form a collection from the result of two URL's. (i.e. a, b, d and e come from URL 1, and c comes from URL 2)?
This way all I would need to change was the template and it should all work the same. Instead of having to alter a load of other stuff as well.
Thanks.
You have few options:
Update the endpoint to send required data. This is the proper way to do it. Collection should Ideally have single endpoint
Send a seperate AJAX request to get data from one URL before fetching collection, then in collection's parse method add the data to the response fetched from collection's URL
Do something like:
$.when(collection.fetch(), collection.fetchExtraData())
.done(()=> { /* create view here */ });
fetchExtraData here is a custom function that sends extra request and updates collection properly with the data. This way both requests are sent simultaneously. You need to make sure parse doesn't reset the data from other endpoint.

Backbone view/template fails to load from REST

I have properly coded a simple REST api and several backbone models. My parent model is called Topic and child model called Questions.
I'm trying to call a get method on the REST api and display the received Topic object to the user in a presentable manner. I am receiving the json (can be seen in the network tab on Chrome), but it is not getting sent to the view correctly.
Model:
var Topic = Backbone.Model.extend({
urlRoot: ROOT + '/topic',
idAttribute: 'topicId',
initialize: function () {
this.questions = new Questions([], {parent: this});
},
toJSON: function () {
var json = Backbone.Model.prototype.toJSON.call(this);
json.questions = this.questions.toJSON();
return json;
}
});
var Topics = Backbone.Collection.extend({
model: Topic,
url: ROOT + 'topic',
parse: function (response) {
return response.results;
}
})
REST URL:
http://localhost/Project/index.php/rest/resource/topic/
Backbone View: This is where I think the error is...(console log below prints an empty object)
var TopicListView = Backbone.View.extend({
el: '.page',
render: function () {
var that = this;
var topics = new Topics();
topics.fetch({
success: function (topics) {
console.log(topics);
var template = _.template($('#topic-list-template').html(), {topics: topics.models});
that.$el.html(template);
}
})
}
});
Using the above functions:
var topic = new Topic();
topic.fetch();
topicListView = new TopicListView();
var Router = Backbone.Router.extend({
routes: {
"": "home"
}
});
var router = new Router;
// render topic list for 'home'
router.on('route:home', function () {
topicListView.render();
});
Edit: Solution: Overriding the parse function in the collection proved to be the error. I wonder why...
The argument topics in your success handler is shadowing the variable topics.
The argument contains the parsed JSON response, not the Backbone Collection. You don't need that, so you can remove the argument.
The reference to topics will now be to your Collection, so topics.models will have the value you expect.
topics.fetch({
success: function () { // argument removed here so `topics` is no longer shadowed
var template = _.template($('#topic-list-template').html(), { topics: topics.models });
that.$el.html(template);
}
})

How can I set context of the error handler of Backbone model fetch?

I'm using a Router to organise my Backbone app. In my edit route I'm calling fetch on a model instance to get the model's data for the edit form:
App.Router = Backbone.Router.extend({
routes: {
"": "index",
"edit(/:id)": "edit"
},
index: function () {
_.bindAll(this, "getItemByID", "onModelFetchError", "showError");
},
edit: function (id) {
this.formEditItem = new App.Views.FormEditItem({model: this.getItemByID(id), parent: this});
},
getItemByID: function(id) {
var item = new App.Models.Item({id: id});
item.fetch({
success: function(model, response, options) {
console.log('Success');
return model;
},
error: this.onModelFetchError
})
},
onModelFetchError: function (model, response, options) {
this.showError(response.responseText);
},
showError: function(msg) {
this.error = new App.Views.Error({parent: this, message: msg});
}
});
The fetch call works fine, but I'm having trouble handling errors. I want to instantiate an Error view and display the message in it. But when I try this code, I get "Uncaught TypeError: Object [object global] has no method 'showError'". It seems that assigning onModelFetchError as the handler for fetch errors puts it in the global scope, even when I bind it to the Router with _.bindAll.
Is there any simple way to ensure onModelFetchError remains in the Router scope?
You are calling to _.bindAll() inside of the index function which is fired by the route "", so if you don't fire that route they'll never get bind to the context object. I would suggest to create an initialize method for your router so you can bind all the functions for any route inside of it.
initialize: function() {
_.bindAll(this, "getItemByID", "onModelFetchError", "showError");
}
Try with
getItemByID: function(id) {
var item = new App.Models.Item({id: id});
var self = this; // this changed
item.fetch({
success: function(model, response, options) {
console.log('Success');
return model;
},
error: self.onModelFetchError // this changed
})
},

Backbone: how to load a Collection in the view (inc require)

I am trying to load data from an API into a view. However the data doesn't turn up in my view.
I tried getting the collection information in de router, as well as in the model.
However the date won't even console.log the data. Let alone that I can load the data into the view.
I am using require to load the JavaScript files. Can you have a look and see what I am doing wrong here?
I do see this console.log:
console.log("People Collection is initialized");
And I can also see the page loaded and the json. But not the console.log of the data in the url function... In fact I get this error in the console:
Error: A "url" property or function must be specified
In the Backbone Router:
var OF = OF || {};
OF.AdminRouter = Backbone.Router.extend({
routes: {
"users": "goToUsers",
"users/*other": "goToUsers"
},
goToUsers: function() {
require(['./models/users', './views/users_view', './views/menu_view', './collections/user_collection'], function(UsersMdl, UsersView, MenuView, UsersCollection) {
OF.usersView = new OF.UsersView;
OF.usersView.render();
});
}
});
The Collection:
var OF = OF || {};
OF.UsersCollection = Backbone.Collection.extend({
initialize: function() {
console.log("People Collection is initialized");
},
url: function() {
var that = this;
var sendObj = {
"admin": OF.login.attributes.admin,
"session": OF.login.attributes.session
};
$.ajax({
url: 'php/api/users/',
type: "POST",
dataType: "json",
data: sendObj,
success: function(data) {
console.log(data);
},
error: function(data) {
console.log("ERR: " + data);
}
});
},
model: OF.UsersMdl
});
The Model:
var OF = OF || {};
OF.UsersMdl = Backbone.Model.extend({
default: {
username: '',
homefoldersize: '',
email: ''
},
initialize: function(){
//on change functions can be done here
OF.usersCollection = new OF.UsersCollection();
OF.usersCollection.fetch();
},
result: {
success: false,
message: ''
},
validate: function(att) {
}
});
The View:
var OF = OF || {};
OF.UsersView = Backbone.View.extend({
el: '#content',
remove: function() {
this.$el.empty();
this.stopListening();
return this;
},
initialize: function() {
//set the new address variable.
OF.usersMdl = OF.usersMdl || new OF.UsersMdl();
},
render: function() {
/*
//first check if you are allowed to see this page
if (!OF.login || !OF.login.isValid()) {
OF.router.navigate('login', {trigger: true});
return;
}
*/
//save this in that
var that = this;
//when importing of login page (and fill it with info) is done
$.when(OF.template.get('users-usersField', function(data) {
var htmlSource = $(data).html();
var template = Handlebars.compile(htmlSource);
var compiled = template(OF.usersMdl.attributes);
//now place the page
that.$el.html(compiled);
//then start the menu
})).then(function(){
setTimeout(function(){
OF.menuView = new OF.MenuView;
OF.menuView.render();
}, 100);
});
$('#logout').show();
}
});
Thanks.
It seems to call the initialize of the collection twice and then continues to call the json function.
In your model's initialization you have
OF.usersCollection = new OF.UsersCollection();
OF.usersCollection.fetch();
But when you fetch your collection, it's going to initialize models for every result it gets back ... which will then trigger fresh collection fetches.
You don't need to create collections for your models inside your models, especially if the model is being created by the collection. Whenever you add a model to a collection (including when the collection creates the model after a fetch) the collection will associate itself with the model.
The general order of things should be:
You define a url function on your collection which returns the URL where you can get the (raw JSON) models of that collection.
You instantiate that collection, and then call fetch on the instance
The collection makes an AJAX call (which you can affect by overriding fetch or sync) and gets back the raw JSON for all of the models.
The collection instantiates new models for each result it gets back; those models are automatically added to the collection, and their .collection is automatically set to the collection.
Once OF.usersCollection.fetch().done(function() {... you can have your views start doing things, as your collection should now be all set.

Backbone reset a collection on fetch

This is my problem:
I have a container view that holds a collection.
On page load I get some models, populate this collection with them, then render the models
I fire and event
When this event fires, I want to make a call to my api (which returns models based on input parameters)
I then want to remove all existing models from the collection, repopulate with my new models, and then render the models
This is how I set up my model/collection/view
var someModel = Backbone.Model.extend({});
var someCollection = Backbone.Collection.extend({
model: someModel,
url: "api/someapi"
});
var someView = Backbone.View.extend({
events: {
"click #refresh": "refreshCollection"
},
initialize: function () {
this.collection.bind("reset", this.render, this);
},
render: function () {
// render stuff
},
refreshCollection: function (e) {
this.collection.fetch({data: {someParam: someValue});
this.render();
}
});
var app = function (models) {
this.start = function () {
this.models = new someCollection();
this.view = new someView({collection: this.models});
this.view.reset(models);
};
};
My point of interest is here:
refreshCollection: function (e) {
this.collection.fetch({data: {someParam: someValue});
this.render();
}
I pass in some paramaters, and my api returns a json array of models. I want to get rid of all existing models in the collection, and put all of my returned models into the collection, then update the view (with render())
I understand this is possible with collection.set, or collection.reset. Both of these take in an array of models. I don't have an array of models to pass in.
I tried:
this.collection.fetch({
data: {someParam: someValue},
success: function (response) {
doSomethingWith(response.models)
}
});
But I don't know what to do with the models when I get them.
Any pushed in the right direction would be appreciated!
From the fine manual:
fetch collection.fetch([options])
[...] When the model data returns from the server, it uses set to (intelligently) merge the fetched models, unless you pass {reset: true}, in which case the collection will be (efficiently) reset.
So you just need to include reset: true in the options and fetch will call reset to replace the collection's contents with the fetched models:
this.collection.fetch({
data: { ... },
reset: true
});

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