How to override Backbone.js 's Paginator.requestPager setDefault function? - backbone.js

I'm using Paginator.requestPager in backbone.
And I wanted to change query paremeter value at time Collection fetch is called.
So, I added setDefaults function in Equipments.
But in this case Backbone.Paginator 's setDefault function will not be called.
How to add some attribute's in Paginator requestPager?
var Equipments = Backbone.Paginator.requestPager.extend({
setDefaults: function() {
var self = this;
this.query = "nike";
}
…
});

You just have to execute original setDefaults
setDefaults : function() {
// set own properties
this.query = 'nike';
// run super method
Backbone.Paginator.prototype.setDefaults.apply(this, arguments);
}

Thank you so much,
I can call like this.
Backbone.Paginator.requestPager.prototype.setDefaults.apply(this, arguments);
But I recognized I dont have to call super method.
I add a function and
setQuery: function (value){
this.query = value;
},
server_api: {
'query' : function() { return this.query },
},
I can do set parameter before fetch.

Related

Backbone/Underscore _.each(...) doesn't seem to work according to docs

In this code...
_.each(this.photos, function(element,index,list) {
console.log('element...');
console.log(element);
var photoView = new PhotoView({photo:element});
self.$el.append(photoView.render());
});
element is the entire this.photos collection. Why is not just one photo element of the 10 in the collection?
EDIT: Here is my method that populates the photos collection....
loadPhotos: function(memberId) {
var self = this;
this.photos = new PhotosCollection([]);
this.photos.on('error', this.eventSyncError, this);
this.photos.fetch({
url: this.photos.urlByMember + memberId,
success: function(collection,response,options) {
console.log('Fetch photos success!');
self.render();
}
});
},
The collection loads with models just fine. In the Chrome console, I can see the collection of models. I'm not sure what's wrong. I cannot iterate the collection with any of the methods recommended by posters below.
You are using the _.each method incorrectly. The underscore methods needs to called directly on the collection:
this.photos.each(function(element,index,list) {
console.log('element...');
console.log(element);
var photoView = new PhotoView({photo:element});
self.$el.append(photoView.render());
});
Or you if want to use the _.each from you need to pass in the models property and not the collection object itself as the list:
_.each(this.photos.models, function(element,index,list) {
console.log('element...');
console.log(element);
var photoView = new PhotoView({photo:element});
self.$el.append(photoView.render());
});
One should use this.photos.each(function(elt, index, list){...}) instead of _.each(this.photos,...) because this.photos is not an underscorejs _.chain object.
Thank you for your suggestions! I would never have figured this out without all your advice above. So here was the problem...
In the parent view, this loads up photo records for a particular member...
loadPhotos: function(memberId) {
var self = this;
this.photos = new PhotosCollection([]);
this.photos.on('error',this.eventSyncError,this);
this.photos.fetch({
url: this.photos.urlByMember + memberId,
success: function(collection,response,options) {
self.render();
}
});
},
Still in the parent view, Backbone.Subviews uses this to call each child view when it renders. Note how I'm passing this.photos to the subvw-photos...
subviewCreators: {
"subvw-profile": function() {
var options = {member: this.member};
// do any logic required to create initialization options, etc.,
// then instantiate and return new subview object
return new ProfileView( options );
},
"subvw-photos": function() {
var options = {photos: this.photos};
return new PhotosView( options );
},
"subvw-comments": function() {
var options = {};
return new CommentsView( options );
}
},
This is in the subvw-photos child view. Note how the intialize is accepting the collection as a parameter. See this problem?...
initialize: function(photos) {
Backbone.Courier.add(this);
this.photos = photos;
},
render: function() {
console.log('rendering photosview now...');
var self = this;
this.photos.each(function(element,index,list) {
var photoView = new PhotoView({photo:element});
$(self.el).append(photoView.render());
});
return this;
},
I was passing an object wrapping the photos collection in to initalize but then treating it like it was just a ref to the photos collection. I had to change the subvw-photos initialize to the following...
initialize: function(args) {
Backbone.Courier.add(this);
this.photos = args.photos;
},
Then of course all the other code magically began working :-/
Thank you again for your tips! You definitely kept me on track :-)

Override backbone 'set' method

I want to override backbone set method so that whenever I set a value to backbone Model the callbacks registered on that attribute get called without checking for same previous value of that attribute .
var model = Backbone.Model.extend({
defaults : {
prop1 : true
}
});
var view = Backbone.View.extend({
initialize : function(){
this.listenTo(this.model,"change:prop1", this.callback);
},
callback : function(){
// set is called on prop1
}
});
var m1 = new model();
var v1 = new view({model:m1});
m1.set("prop1",true); // It doesn't trigger callback because I'm setting the same value to prop1
You can write a new method in backbone model set like this :
var model = Backbone.Model.extend({
defaults: {
prop1: true;
},
// Overriding set
set: function(attributes, options) {
// Will be triggered whenever set is called
if (attributes.hasOwnProperty(prop1)) {
this.trigger('change:prop1');
}
return Backbone.Model.prototype.set.call(this, attributes, options);
}
});
Actually, the signature of function set differs from the one depicted in the accepted answer.
export var MyModel = Backbone.Model.extend({
set: function (key, val, options) {
// custom code
var result = Backbone.Model.prototype.set.call(this, key, val, options);
// custom code
return result;
}
});
See:
http://backbonejs.org/docs/backbone.html
https://github.com/jashkenas/backbone/issues/1391

Can't get waiting for function to return (with promises?) working in angular controller

I'm trying to get the following findTimelineEntries function inside an Angular controller executing after saveInterview finishes:
$scope.saveInterview = function() {
$scope.interviewForm.$save({employeeId: $scope.employeeId}, function() {
$scope.findTimelineEntries();
});
};
The save action adds or edits data that also is part of the timeline entries and therefore I want the updated timeline entries to be shown.
First I tried changing it to this:
$scope.saveInterview = function() {
var functionReturned = $scope.interviewForm.$save({employeeId: $scope.employeeId});
if (functionReturned) {
$scope.findTimelineEntries();
}
};
Later to this:
$scope.saveInterview = function() {
$scope.interviewForm.$save({employeeId: $scope.employeeId});
};
$scope.saveInterview.done(function(result) {
$scope.findTimelineEntries();
});
And finaly I found some info about promises so I tried this:
$scope.saveInterview = function() {
$scope.interviewForm.$save({employeeId: $scope.employeeId});
};
var promise = $scope.saveInterview();
promise.done(function() {
$scope.findTimelineEntries();
});
But somehow the fact that it does work this way according to http://nurkiewicz.blogspot.nl/2013/03/promises-and-deferred-objects-in-jquery.html, doesn't mean that I can use the same method on those $scope.someFuntcion = function() functions :-S
Here is a sample using promises. First you'll need to include $q to your controller.
$scope.saveInterview = function() {
var d = $q.defer();
// do something that probably has a callback.
$scope.interviewForm.$save({employeeId: $scope.employeeId}).then(function(data) {
d.resolve(data); // assuming data is something you want to return. It could be true or anything you want.
});
return d.promise;
}

Backbone Model gives this.set not a function in Model.initialize

I've a model listen on the vent for a event update:TotalCost, which is triggered from (unrelated) Collection C when any model M belonging to collection C changes.
This event is coded in the initialize method as below. On receiving the event I get the following error:
TypeError: this.set is not a function
this.set({ "totalsale": value});
CostModel = Backbone.Model.extend({
defaults: {
totalSale: 0,
totalTax: 0
},
initialize: function(attrs, options) {
if(options) {
if(options.vent) {
this.vent = options.vent;
}
}
this.vent.on("update:TotalCost", function(value) {
this.set({ "totalSale": value}); **//ERROR HERE**
});
}
});
It is highly possible you've forgot to add the new keyword before your model for example you have:
var user = UserModel();
// instead of
var user = new UserModel();
Have you tried using a closure?
CostModel = Backbone.Model.extend({
defaults: {
totalSale: 0,
totalTax: 0
},
initialize: function(attrs, options) {
var self = this;
if(options) {
if(options.vent) {
this.vent = options.vent;
}
}
this.vent.on("update:TotalCost", function(value) {
self.set({ "totalSale": value});
});
}
});
Perhaps you want this to refer to current CostModel instance, to do so you need to pass this to this.vent.on call so event callback will be executed in context of model:
this.vent.on("update:TotalCost", function(value) {
this.set({ "totalSale": value});
}, this);
it may be due to 'set' works on model not on object. so you can, first convert your object in to model then try..
in example:
new Backbone.Model(your_object).set('val', var);
Another cause of this error can be if you try to create a new model without using the "new" keyword
I was getting this mysterious error when using it with Parse. I had:
Parse.User().current().escape("facebookID")
... when I should have had:
Parse.User.current().escape("facebookID")
Removed the extra () and it works fine now.
Another cause:
// render() method in view object
setInterval(this.model.showName, 3000);
// showName() method in model object
showName: function(){
console.log(this.get('name')); // this.get is not a function
}

Backbone model.destroy(): Is explicit removal from collection necessary?

I have a simple question. I am looking at a function with 2 lines of code:
deleteTask: function() {
this.parent.collection.remove(this.model);
this.model.destroy();
}
If I comment out the first line, which is supposed to remove the model from its collection, things seem to work as intended (as in, the model is removed automatically). From Backbone's website, this is the relevant discription for a model's "destroy" function:
Triggers a "destroy" event on the model, which will bubble up through any collections that contain it.
Am I safe to assume that the removal of this.parent.collection.remove(this.model); will not affect the functionality of the code in any way? This is what I think, but I wanted to make sure of it.
Thank you!
If you destroy a model, it is removed from any collections that was containing it. You can see that in the backbone source
//Internal method called every time a model in the set fires an event.
_onModelEvent: function(event, model, collection, options) {
...
if (event === 'destroy') this.remove(model, options);
So yes, I wouldn't think you would need to remove the model from your collection explicitly.
But don't trust me, test for yourself :)
deleteTask: function() {
that = this;
this.model.destroy({
success: function() {
console.log(that.parent.collection);
}
});
}
Check the console for yourself to see whether the model was removed from the collection.
The solution is to override the Backbone model destroy function. I made this on an abstract model with success and callback strategy:
Parameter "data" corresponds to the original parameter "resp".
destroy: function(successCallback, errorCallback)
{
var options = { wait: true };
var model = this;
successCallback = successCallback || function() {};
errorCallback = errorCallback || function() {};
var destroy = function()
{
model.trigger('destroy', model, model.collection, options);
};
options.success = function(data)
{
if ('SUCCESS' === data.responseCode)
{
if (options.wait || model.isNew())
destroy();
successCallback(data);
if (!model.isNew())
model.trigger('sync', model, data, options);
}
else
{
errorCallback(data);
}
};
if (this.isNew())
{
options.success();
return false;
}
var xhr = this.sync('delete', this, options);
if (!options.wait)
destroy();
return xhr;
}

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