Backbone 101: Collections

by kyllle

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0-alpha1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.2.2/backbone-min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/normalize/3.0.3/normalize.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone-localstorage.js/1.1.16/backbone.localStorage-min.js"></script>
<h2 class="pg-heading">Creating a collection</h2>

CSS

@import url(http://fonts.googleapis.com/css?family=Roboto:300,400,500);

* {
  -webkit-font-smoothing: antialiased;
}

body {
    font-family: Roboto;
    padding: 16px;
    line-height: 1.5;
    font-weight: normal;
    color: #ccc;
    background: #292929;
    font-size: 18px;
}

h1, h2, h3 {
    font-weight: normal;
}

h3 ~ p {
    margin-top: 0;
}

p {
    opacity: 0.86;
}

.pg-heading {
    margin-bottom: 0;
}

a {
    color: #95baf6;
    transition: opacity .3s;
}

a:hover {
    opacity: 0.75;
}

pre {
    display: block;
    padding: 9.5px;
    margin: 0 0 10px;
    font-size: 13px;
    line-height: 1.428571429;
    color: #333;
    word-break: break-all;
    word-wrap: break-word;
    background-color: #f5f5f5;
    /* border: 1px solid #ccc; */
    border-radius: 4px;
}

pre.app {
    opacity: 0.35;   
    transition: opacity .3s;
    position: relative;
}

pre.app:after {
    content: 'App Example';
    padding: 3px 8px;
    background: #95baf6;
    position: absolute;
    top: 0;
    right: 0;
    border-radius: 0 4px 0 0;
}

pre.app:hover {
    opacity: 1;
}

JavaScript

console.clear();

var data = [
    {
        id: 1,
        title: 'Pulp Fiction'
    }, {
        id: 2,
        title: 'The Usual Suspects'
    }
]

var MovieModel = Backbone.Model.extend({
    defaults: {
        watchlist: false
    }
});

// Creating a Backbone Collection
var MovieCollection = Backbone.Collection.extend({
    
    model: MovieModel,
    
    initialize: function() {
               
        this.on('add', function(model, collection, options) {
            console.info(model.toJSON(), 'was added to', collection.toJSON());
        });
        
        this.on('remove', function(model, collection, options) {
            console.info(model.toJSON(), 'was removed from', collection.toJSON());
        });
        
        this.on('reset', function(collection, options) {
            console.info('~ Reset called', collection, options); //contains a previousModels array
        });
        
        this.on('change', function(model, options) {
            console.info('~ Model changed', model.toJSON());
        });
        
        this.on('change:watchlist', function(model, options) {
            console.log('~ Model watchlist attribute changed', model.toJSON());
        });
    },
    
    // Collection Method to return all models with watchlist: true
    getWatchlistMovies: function() {
        return this.where('watchlist', true);
    },
    
    // Collection Method to return number of models with watchlist: true
    getWatchlistLength: function() {
        return this.where({'watchlist': true}).length;
    }
});


// Create some instances
var movie = new MovieModel;
var movies = new MovieCollection;


// Adding model data to our Collection
// 1) Passing data straight in on instantiation
// var movies = new MovieCollection(data);
// 2) Adding the data to the instance

	movies.add([{
        id: 1,
        title: 'Pulp Fiction'
    }, {
        id: 2,
        title: 'The Usual Suspects'
    }]);

// 3) Reset the collection with new data
//...