Backbone issues multiple ajax requests unexpectedly - javascript

I put the fetch url with deferred method and I expect it will only invoke the remote ajax request one time.
However, it calls three times when I load the page.
How could I fix it? Thanks
js scripts
var Comments = Backbone.Collection.extend({
model: Comment,
url: fetch_comments_url,
initialize: function() {
this.fetch({
success: this.fetchSuccess,
error: this.fetchError
});
this.deferred = new $.Deferred();
},
deferred: Function.constructor.prototype,
fetchSuccess: function(collection, response) {
collection.deferred.resolve();
},
fetchError: function(collection, response) {
throw new Error("Products fetch did get collection from API");
},
var comments = new Comments();
...
comments.deferred.done(function() {
commentView.render();
emptyCommentView.render();
});
compelte js scripts
var Comments = Backbone.Collection.extend({
model: Comment,
url: fetch_comments_url,
initialize: function() {
this.fetch({
success: this.fetchSuccess,
error: this.fetchError
});
this.deferred = new $.Deferred();
},
deferred: Function.constructor.prototype,
fetchSuccess: function(collection, response) {
collection.deferred.resolve();
},
fetchError: function(collection, response) {
throw new Error("Products fetch did get collection from API");
},
wellFormedComments: function () {
var MESSAGE_LIMIT_LENGTH = 80
var models = comments.select(function (model) {
var msg = model.get("message")
if (msg!=null) {
msg = msg.replace(/^\s+|\s+$/g, '')
if (msg.length >= MESSAGE_LIMIT_LENGTH) {
model.set("preview_message", msg.substr(0, MESSAGE_LIMIT_LENGTH/2));
} else{
};
return true
}
else{
return false
};
});
return new Comments(models);
},
emptyComments: function () {
var models = comments.select(function (model) {
var msg = model.get("message")
return false===_(msg).notBlank();
});
return new Comments(models);
}
});
var comments = new Comments();
var CommentView = Backbone.View.extend({
el: $("#comments_section"),
render: function() {
var notNullComments = comments.wellFormedComments();
if (notNullComments.length > 0) {
$("#dadasay_comments_plugin").show();
}
var html = commentsTmpl(notNullComments.toJSON());
$(this.el).append(html);
},
});
var EmptyCommentView = Backbone.View.extend({
el: $("#empty_comments_list"),
render: function() {
var source = $('#empty_comments_list_tmpl').html();
var emptyComments = comments.emptyComments();
var html = emptyCommentsTmpl(emptyComments.toJSON());
$(this.el).html(html);
},
});
var commentView = new CommentView({
collection: comments
});
var emptyCommentView = new EmptyCommentView({
collection: comments
});
comments.deferred.done(function() {
commentView.render();
emptyCommentView.render();
});

The problem is that your comments collection triggers fetch when initialized. It's methods wellFormedComments and emptyComments creates new comments collections so they triggers fetch as well.
You can fix this by manually triggering fetch when required, something like:
var Comments = Backbone.Collection.extend({
model: Comment,
url: fetch_comments_url,
wellFormedComments: function() {
var MESSAGE_LIMIT_LENGTH = 80
var models = this.select(function(model) {
var msg = model.get("message")
if (msg != null) {
msg = msg.replace(/^\s+|\s+$/g, '')
if (msg.length >= MESSAGE_LIMIT_LENGTH) {
model.set("preview_message", msg.substr(0, MESSAGE_LIMIT_LENGTH / 2));
} else {};
return true
} else {
return false
};
});
return new Comments(models);
},
emptyComments: function() {
var models = this.select(function(model) {
var msg = model.get("message")
return false === _(msg).notBlank();
});
return new Comments(models);
}
});
var CommentView = Backbone.View.extend({
el: $("#comments_section"),
render: function() {
var notNullComments = comments.wellFormedComments();
if (notNullComments.length > 0) {
$("#dadasay_comments_plugin").show();
}
var html = commentsTmpl(notNullComments.toJSON());
$(this.el).append(html);
},
});
var EmptyCommentView = Backbone.View.extend({
el: $("#empty_comments_list"),
render: function() {
var source = $('#empty_comments_list_tmpl').html();
var emptyComments = comments.emptyComments();
var html = emptyCommentsTmpl(emptyComments.toJSON());
$(this.el).html(html);
},
});
var comments = new Comments();
var commentView = new CommentView({
collection: comments
});
var emptyCommentView = new EmptyCommentView({
collection: comments
});
comments.fetch({ // <--------- Do this manually once
success: function() {
commentView.render();
emptyCommentView.render();
},
error: function() {}
});
I think you can better structure your code as shown below, hope the comments explain the changes
var Comments = Backbone.Collection.extend({
model: Comment,
url: fetch_comments_url,
wellFormedComments: function() {
var MESSAGE_LIMIT_LENGTH = 80
var models = this.select(function(model) {
var msg = model.get("message")
if (msg != null) {
msg = msg.replace(/^\s+|\s+$/g, '')
if (msg.length >= MESSAGE_LIMIT_LENGTH) {
model.set("preview_message", msg.substr(0, MESSAGE_LIMIT_LENGTH / 2));
}
return true
}
return false
});
return new Comments(models);
},
emptyComments: function() {
var models = this.select(function(model) {
var msg = model.get("message")
return false === _(msg).notBlank();
});
return new Comments(models);
}
});
var CommentView = Backbone.View.extend({
el: $("#comments_section"),
template: commentsTmpl, // template reference, better create it here
initialize: function() {
this.render(); // self rendering
},
render: function() {
if (this.collection.length) { // use this.collection to refer to view's collection rather than external variables
$("#dadasay_comments_plugin").show(); //This shouldn't be a global selection
}
var html = this.template(this.collection.toJSON());
this.$el.append(html);
//---^ use cached jQuery object rather than creating new one
},
});
var EmptyCommentView = Backbone.View.extend({
el: $("#empty_comments_list"),
template: emptyCommentsTmpl,
initialize: function() {
this.render();
},
render: function() {
var source = $('#empty_comments_list_tmpl').html(); // unused?
var html = this.template(this.collection.toJSON());
this.$el.html(html);
},
});
var comments = new Comments();
comments.fetch({ // <--------- Do this manually once
success: function(collection, response) {
//----------------^ comments collection, all comments
var commentView = new CommentView({
collection: collection.wellFormedComments() // pass the resuting collection
});
var emptyCommentView = new EmptyCommentView({
collection: collection.emptyComments() // pass the resuting collection
});
},
error: function() {}
});

Related

Cannot retrieve collection outside of the view

I'm making a simple list of people with option when clicking on person's name the Router will take a name as a parameter 'student/:name' and find a right person's object in a collection. I instantiate collection in a GroupView class by fetching it from the server. And that's where the Error appears: to get the access to collection (so I can find right object) in my viewStudent() method in Router class, I'm making one more instance of GroupView(), and console shows an error and that's right, 'cause there're no objects in collection.
I cannot wrap my head around this, why in GroupView() I receive data from the server and my collection just works fine, but second time I instantiate GroupView() in a Router - there's no collection? Maybe there's any other way I can get access to the collection in my Router? Any help would be greatly appreciated.
var StudentModel = Backbone.Model.extend({
defaults: {
name: 'Volodya',
lastName: 'Peterson',
age: 22,
gender: 'male'
}
});
var StudentsCollection = Backbone.Collection.extend({
model: StudentModel,
url: '/students.json'
});
var StudentView = Backbone.View.extend({
tagName: 'li',
template: _.template($('#studentTpl').html()),
events: {
'click': function () {
eventAggregator.trigger('student:selected', this.model);
}
},
render: function () {
this.$el.html(this.template(this.model.toJSON()));
return this;
}
});
var GroupView = Backbone.View.extend({
tagName: 'ul',
initialize: function () {
this.collection = new StudentsCollection();
this.collection.on('update', this.render, this);
this.collection.fetch();
},
render: function () {
var self = this;
this.collection.each(function (student) {
var studentView = new StudentView({
model: student
});
self.$el.append(studentView.render().el);
});
$('body').html(this.$el);
}
});
var RouterView = Backbone.View.extend({
tagName: 'ul',
render: function () {
var self = this;
_.each(this.model.toJSON(), function (value) {
self.$el.append('<li>' + value + '</li>');
});
return this;
}
});
var GroupController = function () {
this.start = function () {
var groupView = new GroupView();
};
};
var Router = Backbone.Router.extend({
routes: {
'': 'index',
'student/:name': 'viewStudent'
},
index: function () {
groupController.start();
},
viewStudent: function (name) {
var groupView = new GroupView();
var selectedStudent = groupView.collection.find(function (student) {
return student.get('name') === name;
});
$('body').append((new RouterView({ model : selectedStudent})).render().el);
}
});
var eventAggregator= _.extend({}, Backbone.Events),
groupController;
$(function () {
var router = new Router();
groupController = new GroupController();
Backbone.history.start();
eventAggregator.on('student:selected', function (student) {
var urlpath= 'student/'+ student.get('name');
router.navigate(urlpath, {trigger: true});
});
});

How to pass filtered data into view from collection in backbone

I know Im pretty close to figuring this out. Im trying to filter out my collection based on if favorite eq true. If I console.log - I can see it's doing its job. But it's not updating my view.
Anyone have any idea what I'm missing or doing wrong?
Here is my code:
var Products = Backbone.Model.extend({
// Set default values.
defaults: {
favorite: false
}
});
var ProductListCollection = Backbone.Collection.extend({
model: Products,
url: '/js/data/wine_list.json',
parse: function(data) {
return data;
},
comparator: function(products) {
return products.get('Vintage');
},
favoritesFilter1: function(favorite) {
return this.filter(function(products) {
return products.get('favorite') == true;
});
},
favoritesFilter: function() {
return this.filter(function(products) {
return products.get('favorite') == true;
});
},
});
var products = new ProductListCollection();
var ProductListItemView = Backbone.View.extend({
el: '#wine-cellar-list',
initialize: function() {
products.bind('reset', this.render, this);
products.fetch();
this.render();
},
render: function() {
console.log(this.collection);
var source = $('#product-template').html();
var template = Handlebars.compile(source);
var html = template(this.collection.toJSON());
this.$el.html(html);
return this;
},
});
// Create instances of the views
var productView = new ProductListItemView({
collection: products
});
var CellarRouter = Backbone.Router.extend({
routes: {
'': 'default',
"favorites": "showFavorites",
"purchased": "showPurchased",
"top-rated": "showTopRated",
},
default: function() {
productView.render();
},
showFavorites: function() {
console.log('Favorites');
productView.initialize(products.favoritesFilter());
},
showPurchased: function() {
console.log('Purchased');
},
showTopRated: function() {
console.log('Top Rated');
}
});
$(function() {
var myCellarRouter = new CellarRouter();
Backbone.history.start();
});
There's many mistakes in your code, I'll try to clarify the most I can :
Your collection should be just like this :
var ProductListCollection = Backbone.Collection.extend({
model: Products,
url: '/js/data/wine_list.json',
comparator: 'Vintage' // I guess you want to sort by this field
});
Your view like this :
var ProductListItemView = Backbone.View.extend({
el: '#wine-cellar-list',
initialize: function() {
this.collection.bind('reset', this.full, this);
this.collection.fetch();
},
full: function() {
this.render(this.collection.models);
},
favorites: function(favorite) {
this.render(this.collection.where(favorite)); // here's the answer to your question
},
render: function(models) {
console.log(models);
var source = $('#product-template').html();
var template = Handlebars.compile(source);
var html = template(models.toJSON()); // You may have to change this line
this.$el.html(html);
return this;
},
});
And in your router :
showFavorites: function() {
console.log('Favorites');
productView.favorites(true); // or false, as you like
}

Backbonejs usage of el

I've created 2 separate views, 1 to render the template and the other one is where I bind the events, then I tried merging them into one in which case it causes an Uncaught TypeError: Object [object Object] has no method 'template'. It renders the template and the events are working as well, but I get the error.
edit.js, this is the combined view, which I think it has something to do with their el where the error is coming from
window.EditView = Backbone.View.extend ({
events: {
"click #btn-save" : "submit"
},
initialize: function() {
this.render();
},
render: function() {
$(this.el).html(this.template());
return this;
},
submit: function () {
console.log('editing');
$.ajax({ ... });
return false;
}
});
var editView = new EditView();
signin.js, this is the view that I can't merge because of the el being used by the ajax call and in SigninView's $(this.el) which causes the rendering of the templates faulty
window.toSigninView = Backbone.View.extend ({
el: '#signin-container',
events: {
"click #btn-signin" : "submit"
},
initialize: function() {
console.log('Signin View');
},
submit: function() {
$.ajax({ ... });
return false;
}
});
var toSignin = new toSigninView();
window.SigninView = Backbone.View.extend({
initialize: function() {
this.render();
},
render: function() {
$(this.el).html(this.template());
return this;
}
});
and I use utils.js to call my templates
window.utils = {
loadTpl: function(views, callback) {
var deferreds = [];
$.each(views, function(index, view) {
if (window[view]) {
deferreds.push($.get('templates/' + view + '.html', function(data) {
window[view].prototype.template = _.template(data);
}));
} else {
alert(view + " not found");
}
});
$.when.apply(null, deferreds).done(callback);
}
};
In my Router.js, this is how I call the rendering of templates
editProfile: function() {
if (!this.editView) {
this.editView = new EditView();
}
$('#global-container').html(this.editView.el);
},
utils.loadTpl (['SigninView', 'EditView'],
function() {
appRouter = new AppRouter();
Backbone.history.start();
});
I think that I figured out your problem.
First merge your views and delete the line var toSignin = new toSigninView();
Second modify your utils.js code like this :
window[view].prototype.template = _.template(data);
new window[view]();

this.collection.each doesn't iterate

I am trying to understand Backbone and tried to create some small REST API fronted, but can not get View to work.
fetch() returns valid JSON array of three elements. And this.collection.models is not empty (typeof object - []) - it has tree child object elements in it. But each iteration doesn't fire.
When check if collection.models exists with console.log(this.collection.models); it looks like all is right:
I would be thankful for any advice!
var Account = Backbone.Model.extend({});
var AccountsCollection = Backbone.Collection.extend({
model: Account,
url: 'api/v1/accounts',
initialize: function () {
this.fetch();
}
});
var AccountsView = Backbone.View.extend({
render: function() {
// Check if there is something
console.log(this.collection.models);
// This doesn't work
_.each(this.collection.models, function(model) {
console.log(model);
});
// Neither this
this.collection.each(function(model) {
console.log(model);
});
}
});
var a = new AccountsView({collection: new AccountsCollection()});
a.render();
First option
var AccountsCollection = Backbone.Collection.extend({
model: Account,
url: 'api/v1/accounts'
});
var AccountsView = Backbone.View.extend({
render: function() { /**/ }
});
var collection = new AccountsCollection();
var view = new AccountsView({collection:collection});
collection.fetch().done(function () {
// collection has been fetched
view.render();
});
Second option
var AccountsCollection = Backbone.Collection.extend({
model: Account,
url: 'api/v1/accounts'
});
var AccountsView = Backbone.View.extend({
initialize: function() {
this.listenTo(this.collection, 'sync', this.render);
},
render: function() { /**/ }
});
var collection = new AccountsCollection();
var view = new AccountsView({collection:collection});
Third option
var AccountsCollection = Backbone.Collection.extend({
model: Account,
url: 'api/v1/accounts',
initialize: function () {
this.deferred = this.fetch();
}
});
var AccountsView = Backbone.View.extend({
initialize: function() {
this.collection.deferred.done(_.bind(this.render, this));
},
render: function() { /**/ }
});
var collection = new AccountsCollection();
var view = new AccountsView({collection:collection});

backbone, insert model while maintaining sort order

When a new model is added (via "set" function of the collection), I want the model be inserted at the index maintaining sort order, instead at the end.
Thanks
var Ts = (function () {
var Result = Backbone.Model.extend({
idAttribute : 'PAG_ID'
});
var ResultList = Backbone.Collection.extend({
model: Result,
comparator: function(result) {
//console.log(result);
return result.get('SORT_KEY');
},
});
var resultsCollection = new ResultList(data);
data = undefined;
var TableView = Backbone.View.extend({
tagName: 'table',
initialize : function() {
_.bindAll(this, 'render', 'renderRow');
this.collection.on("add", this.renderRow, this);
},
render: function() {
$(this.el).attr('id', 'tsTable').addClass('resulttable');
this.renderHeader(this.collection.shift());
this.collection.each(this.renderRow);
return this;
},
renderHeader : function(model) {
var col=new HeaderView({model:model});
this.$el.append(col.render().$el);
return this;
},
renderRow : function(model) {
var row=new RowView({model:model});
this.$el.append(row.render().$el);
return this;
}
});
var HeaderView = Backbone.View.extend({
tagName: 'tr',
model: resultsCollection.models,
initialize: function() {
this.model.on('change',this.render,this);
},
render: function() {
var html=_.template(colTemplate,this.model.toJSON());
this.$el.html(html);
return this;
}
});
var RowView = Backbone.View.extend({
tagName: 'tr',
initialize: function() {
this.model.on('all',this.render,this);
},
remove: function () {
debug.log("Called remove event on model");
$(this.el).remove();
},
model: resultsCollection.models,
render: function() {
var html=_.template(rowTemplate,this.model.toJSON());
this.$el.html(html);
return this;
},
attributes : function () {
return {
id : this.model.get('PAG_ID')
};
}
});
var tableView = new TableView({collection: resultsCollection});
$("body").append( tableView.render().$el );
resultsCollection.set(initialdata);
resultsCollection.set(someotherdata, {merge: true});
I have changed to as below and it works.Not sure if this is the best implementation
renderRow : function(model) {
var row = new RowView({model:model});
var index = model.get('SORT_KEY') - 1;
row.render().$el.insertAfter(this.$el.find('tr:eq('+ index +')'));
return this;
}
If you provide a comparator function on your collection, Collection.set will perform a silent sort after the new models have been spliced in.
From backbones source http://backbonejs.org/docs/backbone.html:
set: function(models, options) {
var sortable = this.comparator && (at == null) && options.sort !== false;
var sortAttr = _.isString(this.comparator) ? this.comparator : null;
...
if (toAdd.length) {
if (sortable) sort = true;
this.length += toAdd.length;
if (at != null) {
splice.apply(this.models, [at, 0].concat(toAdd));
} else {
push.apply(this.models, toAdd);
}
}
if (sort) this.sort({silent: true});
Here is a fiddle demonstrating that collection.set respects a comparator.
http://jsfiddle.net/puleos/sczV3/

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