Backbone.CollectionViewBinder.js

// Backbone.CollectionViewBinder v0.1.0
// (c) 2012 Bart Wood
// Distributed Under MIT License

(function(){

    if(!Backbone){
        throw 'Please include Backbone.js before Backbone.ModelBinder.js';
    }

    if(!Backbone.ModelBinder){
        throw 'Please include Backbone.ModelBinder.js before Backbone.CollectionViewBinder.js';
    }

    Backbone.CollectionViewBinder = function(elManagerFactory){
        _.bindAll(this);

        this._elManagerFactory = elManagerFactory;
        if(!this._elManagerFactory) throw 'elManagerFactory must be defined.';

        // Let the factory just use the trigger function on the view binder
        this._elManagerFactory.trigger = this.trigger;
    };

    Backbone.CollectionViewBinder.VERSION = '0.1.0';

    _.extend(Backbone.CollectionViewBinder.prototype, Backbone.Events, {
        createBoundEls: function(collection, parentEl){
            this.unbind();

            if(!collection) throw 'collection must be defined';
            if(!parentEl) throw 'parentEl must be defined';

            this._collection = collection;
            this._elManagerFactory.setParentEl(parentEl);

            this._collection.each(function(model){
                this._onCollectionAdd(model);
            }, this);

            this._collection.on('add', this._onCollectionAdd, this);
            this._collection.on('remove', this._onCollectionRemove, this);
            this._collection.on('reset', this._onCollectionReset, this);

        },

        unbind: function(){
            if(this._collection !== undefined){
                this._collection.off('add', this._onCollectionAdd);
                this._collection.off('remove', this._onCollectionRemove);
                this._collection.off('reset', this._onCollectionReset);
            }

            this._removeAllElManagers();
        },

        getManagerForEl: function(el){
            var i, elManager, elManagers = _.values(this._elManagers);

            for(i = 0; i < elManagers.length; i++){
                elManager = elManagers[i];

                if(elManager.isElContained(el)){
                    return elManager;
                }
            }

            return undefined;
        },

        getManagerForModel: function(model){
            var i, elManager, elManagers = _.values(this._elManagers);

            for(i = 0; i < elManagers.length; i++){
                elManager = elManagers[i];

                if(elManager.getModel() === model){
                    return elManager;
                }
            }

            return undefined;
        },

        _onCollectionAdd: function(model){
            this._elManagers[model.cid] = this._elManagerFactory.makeElManager(model);
            this._elManagers[model.cid].createEl();
        },

        _onCollectionRemove: function(model){
            this._removeElManager(model);
        },

        _onCollectionReset: function(){
            this._removeAllElManagers();

            this._collection.each(function(model){
                this._onCollectionAdd(model);
            }, this);
        },

        _removeAllElManagers: function(){
            _.each(this._elManagers, function(elManager){
                elManager.removeEl();
                delete this._elManagers[elManager._model.cid];
            }, this);

            delete this._elManagers;
            this._elManagers = {};
        },

        _removeElManager: function(model){
            if(this._elManagers[model.cid] !== undefined){
                this._elManagers[model.cid].removeEl();
                delete this._elManagers[model.cid];
            }
        }
    });

    // The DefaultElManagerFactory is used for els that are just html templates
    // elHtml - how the model's html will be rendered.  Must have a single root element (div,span).
    // bindings (optional) - either a string which is the binding attribute (name, id, data-name, etc.) or a normal bindings hash
    Backbone.CollectionViewBinder.ElManagerFactory = function(elHtml, bindings){
        _.bindAll(this);

        this._elHtml = elHtml;
        this._bindings = bindings;

        if(! _.isString(this._elHtml)) throw 'elHtml must be a valid html string';
    };

    _.extend(Backbone.CollectionViewBinder.ElManagerFactory.prototype, {
        setParentEl: function(parentEl){
            this._parentEl = parentEl;
        },

        makeElManager: function(model){

            var elManager = {
                _model: model,

                createEl: function(){

                    this._el =  $(this._elHtml);
                    $(this._parentEl).append(this._el);

                    if(this._bindings){
                        if(_.isString(this._bindings)){
                            this._modelBinder = new Backbone.ModelBinder();
                            this._modelBinder.bind(this._model, this._el, Backbone.ModelBinder.createDefaultBindings(this._el, this._bindings));
                        }
                        else if(_.isObject(this._bindings)){
                            this._modelBinder = new Backbone.ModelBinder();
                            this._modelBinder.bind(this._model, this._el, this._bindings);
                        }
                        else {
                            throw 'Unsupported bindings type, please use a boolean or a bindings hash';
                        }
                    }

                    this.trigger('elCreated', this._model, this._el);
                },

                removeEl: function(){
                    if(this._modelBinder !== undefined){
                        this._modelBinder.unbind();
                    }

                    this._el.remove();
                    this.trigger('elRemoved', this._model, this._el);
                },

                isElContained: function(findEl){
                    return this._el === findEl || $(this._el).has(findEl).length > 0;
                },

                getModel: function(){
                    return this._model;
                },

                getEl: function(){
                    return this._el;
                }
            };

            _.extend(elManager, this);
            return elManager;
        }
    });


    // The ElManagerFactory is used for els that are created and owned by backbone views.
    // There is no bindings option because the view made by the viewCreator should take care of any binding
    // viewCreator - a callback that will create backbone view instances for a model passed to the callback
    Backbone.CollectionViewBinder.ViewManagerFactory = function(viewCreator){
        _.bindAll(this);
        this._viewCreator = viewCreator;

        if(!_.isFunction(this._viewCreator)) throw 'viewCreator must be a valid function that accepts a model and returns a backbone view';
    };

    _.extend(Backbone.CollectionViewBinder.ViewManagerFactory.prototype, {
        setParentEl: function(parentEl){
            this._parentEl = parentEl;
        },

        makeElManager: function(model){
            var elManager = {

                _model: model,

                createEl: function(){
                    this._view = this._viewCreator(model);
                    $(this._parentEl).append(this._view.render(this._model).el);

                    this.trigger('elCreated', this._model, this._view);
                },

                removeEl: function(){
                    if(this._view.close !== undefined){
                        this._view.close();
                    }
                    else {
                        this._view.$el.remove();
                        console.log('warning, you should implement a close() function for your view, you might end up with zombies');
                    }

                    this.trigger('elRemoved', this._model, this._view);
                },

                isElContained: function(findEl){
                    return this._view.el === findEl || this._view.$el.has(findEl).length > 0;
                },

                getModel: function(){
                    return this._model;
                },

                getEl: function(){
                    return this._view.el;
                }
            };

            _.extend(elManager, this);

            return elManager;
        }
    });

}).call(this);