I'm trying to filter a collection and return the new list so I can render to the page.
I have created a new function on the collection itself but try as I may I cannot get the 2nd IF statement to evaluate TRUE even though I know for sure that there is a match (static match).
I've even tried typeof to make sure that wasn't tripping things up.
Can anyone let me know what I'm missing.
var DisciplinesCollection = Backbone.Collection.extend({
model: Discipline,
filterByCategory: function(cat){
this.each(function(item){
var category = item.attributes.category
console.log(category, cat)
if ('intermediate' == cat){
console.log('static match')
}
if (category == cat){
console.log('dynamic match')
}
});
}
});
I think my issue was the category parameter was a string with a list of potential categories separated by a space. Once I moved these items into a nested object my code was working correctly. Final code example for anyone interested:
var DisciplinesCollection = Backbone.Collection.extend({
model: Discipline,
filterByCategory: function(cat){
return _(this.filter(function(data) {
return _.contains(data.get("category"), cat);
}));
}
});
Related
I have a small app that users can use to search for a movie, and then add it to their watchlist. Currently it is possible to add 1 movie multple times for the same user. Which ofcourse isn't expected behaviour.
My solution would be to find the unique id of the movie that's being added and crosscheck that with my movies_users data. If the movie_id value exists, do this, else do this.
At the moment I do have the unique movie id of the movie that's being added,
$scope.movieListID = response;
console.log ($scope.movieListID.id)
Which gets ouputted like a string, like so,
314365
And I got the movie records from the current user,
$scope.moviesCheck = response.data;
console.log ($scope.moviesCheck)
Which looks like this,
[{"id":2,"title":"Black Panther", "movie_id":"284054"}]
So what would be a good way to check if the result from $scope.movieListID.id already exists in the $scope.moviesCheck data?
* update *
Trying a suggestion below does not give the expected result.
var exists = function (id) {
$scope.moviesCheck.forEach(function (movie) {
console.log (movie.movie_id)
console.log (id)
if (movie.movie_id === id)
console.log ('duplicate')
else
console.log ('not duplicate')
});
}
exists($scope.movieListID.id);
The console.log output from this is,
312221
312221
not duplicate
Which clearly are duplicate results.
You can add a function in your controller to check if the movie exists in the list
var exists = function (id) {
$scope.moviesCheck.forEach(function (movie) {
if (movie.id === id)
return true;
});
return false;
}
// and call it
exists($scope.movieListID.id); // true or false
I'm not 100% if this is a good way to do this, but for me it works and I think it's pretty low on performance,
movieService.loadMovies().then(function(response) {
$scope.moviesCheck = response.data;
var arr = $scope.moviesCheck
function myIndexOf(o) {
for (var i = 0; i < arr.length; i++) {
if (arr[i].movie_id == o.exisitingMovie_id) {
return i;
}
}
return -1;
}
var checkDuplicate = (myIndexOf({exisitingMovie_id:movie.id}));
if (checkDuplicate == -1) {
From your question I've understood that, based on the object exists using id in the array of object, you have to do different action.
You can use $filter for this. Inject the filter for your controller and assign it to the scope. So this will be available whenever you want in this controller.
$scope.cFilter('filter')($scope.movies, {movie_id:$scope.existingMovie.movie_id}, true);
$sope.movies - is the list of movies passed to the filter. You can
send any list based on your need.
{movie_id:$scope.existingMovie.movie_id} - This one is the object
which one we need to find. This can be based on your need. Since we
are searching movie_id, we need to send the object with property
and value. {movie_id:$scope.existingMovie.movie_id}, Here movie_id is
the property and followed by the value with the colon.
true: This indicates that, to search exact matched values. By default
this is false. If this is set to false, then if we want to search 54
in the movie id, this will returns the objects whichever contains 54
as part of the value.
app.controller('controller', ['$filter',function($filter){
$scope.cFilter= $filter;
$scope.Exists=function(){
$scope.movies=[{"id":2,"title":"Black Panther", "movie_id":"284054"},{"id":3,"title":"Black Panther", "movie_id":"32343"},{"id":4,"title":"Black Panther", "movie_id":"98863"}]
$scope.existingMovie={"id":3,"title":"Black Panther", "movie_id":"32343"};
var _obj=$scope.cFilter('filter')($scope.movies, {movie_id:$scope.existingMovie.movie_id}, true);
if(_obj && _obj[0])
{
Console.log('object exists')
}
else
{
Console.log('Object is not found')
}
}
}])
Many Thanks Jeeva Jsb. This got me on the right track, however I thought I would clarify with a practical example that seems to work as expected.
So I have a function called getData which get the AJAX array but we need to check if the record exist before added to scope (else we get duplicates)
if (d.data.length) {
for (var i = 0; i < d.data.length; i++) {
var doesExist = $filter('filter')($scope.notifications, {NotifId:d.data[i].NotifId}, true);
if (doesExist.length == 0){
$scope.notifications.push(d.data[i]);
}
}
}
This should look familier...
when we are iterating through the returned AJAX object we need to check the ID of the (in my case notificiation)
var doesExist = $filter('filter')($scope.notifications, {NotifId:d.data[i].NotifId}, true);
This line creates a new array by filtering the existing array in scope ($scope.notifications) and passing in the same value from you interation.
If the value exists the object will be copied to the new array called doesExist.
A simple check of length will determine if the record needs to be written.
I hope this helps someone.
i'm trying to filter a collection which has models with some nested object. Unfortunately, my result are always empty.
So my models returned in the collection are build like this:
My goal is simple:
I have a view with a list of tag and a content view with all the questions. When a user click on tag, for example, "c#", i want to filter my collection to just return questions with tag "c#"
Before i was doing a fetch on my server and it was working fine, but it was not optimize.
I already have a collection with all the questions so why make a new call, a filter is a better solution i think.
But i didn't succeded with my filter and i don't know if it's possible to do. For now i put my filter in my router because it's more easy to test.
i can't make a filter like this because i have an array of object
getQuestionsByTags: function(query) {
var test = this.questionsCollection.filter(function(model) {
return model.attributes.tags.name == query;
})
console.log('result');
console.log(test);
},
So i was thinking to make a loop but my result is always an empty array.
getQuestionsByTags: function(query) {
var test = this.questionsCollection.filter(function(model) {
_.each(model.attributes.tags, function(tag) {
return tag.name == query;
})
})
console.log('result');
console.log(test);
},
It's maybe simple, but i don't know what to do.
Thanks in advance :)
i've just found a solution that work.
getQuestionsByTags: function(query) {
var flag;
var test2 = this.questionsCollection.filter(function(model) {
flag = false;
_.each(model.attributes.tags, function(tag) {
if(tag.name == query) {
flag = true;
}
})
if(flag) {
return model.attributes;
}
})
console.log('result');
console.log(test2);
},
i put a flag. If he turn true inside the loop, the model has this tag so i return it.
I think it's not very conventional, so if someone have another solution, feel free to post it :)
I have a complex model served from my back end, which has a bunch of regular attributes, some nested models, and a couple of collections.
My page has two tables, one for invalid items, and one for valid items. The items in question are from one of the nested collections. Let's call it baseModel.documentCollection, implementing DocumentsCollection.
I don't want any filtration code in my Marionette.CompositeViews, so what I've done is the following (note, duplicated for the 'valid' case):
var invalidDocsCollection = new DocumentsCollection(
baseModel.documentCollection.filter(function(item) {
return !item.isValidItem();
})
);
var invalidTableView = new BookIn.PendingBookInRequestItemsCollectionView({
collection: app.collections.invalidDocsCollection
});
layout.invalidDocsRegion.show(invalidTableView);
This is fine for actually populating two tables independently, from one base collection. But I'm not getting the whole event pipeline down to the base collection, obviously. This means when a document's validity is changed, there's no neat way of it shifting to the other collection, therefore the other view.
What I'm after is a nice way of having a base collection that I can have filter collections sit on top of. Any suggestions?
I fleshed out my previous attempt and have come up with an extension to Backbone.Collection that does what I need.
collections.FilteredCollection = Backbone.Collection.extend({
initialize: function(items, options) {
if (_.isUndefined(options.baseCollection))
throw "No base collection to watch";
if (!_.isFunction(options.filterFunc)) {
throw "No filter to apply";
}
_.extend(this, options);
this.listenTo(this.baseCollection, 'all', this.reraise);
},
reraise: function (event) {
this.reset(this.baseCollection.filter(this.filterFunc), { silent: true });
var args = [].slice.call(arguments, 1);
this.trigger(event, args);
}
});
The one small issue I have with this is that I have to manually apply filterFunc to the baseCollection, then pass that in as the items parameter when instantiating a FilteredCollection, but that's something I can live with.
The below code is what I'm using to instantiate. Note that there's another almost-exact copy which is for the collection of ONLY VALID items, but any filters can be applied.
var allDocs = theModel.get('Documents');
var invalidOptions = {
baseCollection: allDocs,
filterFunc: function(item) {
return !item.isValidItem();
}
};
var invalidDocs = allDocs.filter(invalidOptions.filterFunc);
var invalidDocsCollection = new collections.FilteredCollection(
invalidDocs, invalidOptions
);
I can successfully do this:
App.SomeCollection = Backbone.Collection.extend({
comparator: function( collection ){
return( collection.get( 'lastName' ) );
}
});
Which is nice if I want to have a collection that is only sorted by 'lastName'. But I need to have this sorting done dynamically. Sometimes, I'll need to sort by, say, 'firstName' instead.
My utter failures include:
I tried passing an extra variable specifying the variable to sort() on. That did not work. I also tried sortBy(), which did not work either. I tried passing my own function to sort(), but this did not work either. Passing a user-defined function to sortBy() only to have the result not have an each method, defeating the point of having a newly sorted backbone collection.
Can someone provide a practical example of sorting by a variable that is not hard coded into the comparator function? Or any hack you have that works? If not, a working sortBy() call?
Interesting question. I would try a variant on the strategy pattern here. You could create a hash of sorting functions, then set comparator based on the selected member of the hash:
App.SomeCollection = Backbone.Collection.extend({
comparator: strategies[selectedStrategy],
strategies: {
firstName: function () { /* first name sorting implementation here */ },
lastName: function () { /* last name sorting implementation here */ },
},
selectedStrategy: "firstName"
});
Then you could change your sorting strategy on the fly by updating the value of the selectedStrategy property.
EDIT: I realized after I went to bed :) that this wouldn't quite work as I wrote it above, because we're passing an object literal to Collection.extend. The comparator property will be evaluated once, when the object is created, so it won't change on the fly unless forced to do so. There is probably a cleaner way to do this, but this demonstrates switching the comparator functions on the fly:
var SomeCollection = Backbone.Collection.extend({
comparator: function (property) {
return selectedStrategy.apply(myModel.get(property));
},
strategies: {
firstName: function (person) { return person.get("firstName"); },
lastName: function (person) { return person.get("lastName"); },
},
changeSort: function (sortProperty) {
this.comparator = this.strategies[sortProperty];
},
initialize: function () {
this.changeSort("lastName");
console.log(this.comparator);
this.changeSort("firstName");
console.log(this.comparator);
}
});
var myCollection = new SomeCollection;
Here's a jsFiddle that demonstrates this.
The root of all of your problems, I think, is that properties on JavaScript object literals are evaluated immediately when the object is created, so you have to overwrite the property if you want to change it. If you try to write some kind of switching into the property itself it'll get set to an initial value and stay there.
Here's a good blog post that discusses this in a slightly different context.
Change to comparator function by assigning a new function to it and call sort.
// Following example above do in the view:
// Assign new comparator
this.collection.comparator = function( model ) {
return model.get( 'lastname' );
}
// Resort collection
this.collection.sort();
// Sort differently
this.collection.comparator = function( model ) {
return model.get( 'age' );
}
this.collection.sort();
So, this was my solution that actually worked.
App.Collection = Backbone.Collection.extend({
model:App.Model,
initialize: function(){
this.sortVar = 'firstName';
},
comparator: function( collection ){
var that = this;
return( collection.get( that.sortVar ) );
}
});
Then in the view, I have to M-I-C-K-E-Y M-O-U-S-E it like this:
this.collections.sortVar = 'lastVar'
this.collections.sort( this.comparator ).each( function(){
// All the stuff I want to do with the sorted collection...
});
Since Josh Earl was the only one to even attempt a solution and he did lead me in the right direction, I accept his answer. Thanks Josh :)
This is an old question but I recently had a similar need (sort a collection based on criteria to be supplied by a user click event) and thought I'd share my solution for others tackling this issue. Requires no hardcoded model.get('attribute').
I basically used Dave Newton's approach to extending native JavaScript arrays, and tailored it to Backbone:
MyCollection = Backbone.Collection.extend({
// Custom sorting function.
sortCollection : function(criteria) {
// Set your comparator function, pass the criteria.
this.comparator = this.criteriaComparator(criteria);
this.sort();
},
criteriaComparator : function(criteria, overloadParam) {
return function(a, b) {
var aSortVal = a.get(criteria);
var bSortVal = b.get(criteria);
// Whatever your sorting criteria.
if (aSortVal < bSortVal) {
return -1;
}
if (aSortVal > bSortVal) {
return 1;
}
else {
return 0;
}
};
}
});
Note the "overloadParam". Per the documentation, Backbone uses Underscore's "sortBy" if your comparator function has a single param, and a native JS-style sort if it has two params. We need the latter, hence the "overloadParam".
Looking at the source code, it seems there's a simple way to do it, setting comparator to string instead of function. This works, given Backbone.Collection mycollection:
mycollection.comparator = key;
mycollection.sort();
This is what I ended up doing for the app I'm currently working on. In my collection I have:
comparator: function(model) {
var methodName = applicationStateModel.get("comparatorMethod"),
method = this[methodName];
if (typeof(method === "function")) {
return method.call(null, model);
}
}
Now I can add few different methods to my collection: fooSort(), barSort(), and bazSort().
I want fooSort to be the default so I set that in my state model like so:
var ApplicationState = Backbone.Model.extend({
defaults: {
comparatorMethod: "fooSort"
}
});
Now all I have to do is write a function in my view that updates the value of "comparatorMethod" depending upon what the user clicks. I set the collection to listen to those changes and do sort(), and I set the view to listen for sort events and do render().
BAZINGA!!!!
So I already got this working using a loop but is wondering is there is a cleaner way to do this.
Basically i got a model that got an array of ids from another model, currently I loop every id and add manually model to a new collection using this filter on the model collection.
getOneById : function(id){
return this.filter(function(data) {
return data.get("id") == id;
});
},
Is there a way to directly return a list doing something like
getAllById : function(arrayIds){
return _(this.filter(function(data) {
??????? return data.get("id") == eachID;
}));
},
Thanks!
you could reduce the looping by checking to see if the id of your object is at an index > -1 in the array:
function(arrayIds){
var models = _.select(collection, function(model){
return (_.indexOf(arrayIds, model.id) > -1);
});
return models;
}
this requires the inclusion of underscore.js in your code, but since you're already using backbone, you already have that.
My solution:
Having collection (Backbone.Collection) and arrayIds
var collection2 = new Backbone.Collection();
collection2.add(collection.models.filter(function(model){
return arrayIds.indexOf(model.id) !== -1;
}));
Four lines :D
console.assert(collection2.length === arrayIds.length) //OK