Dynamically create javascript object (Backbone View)

The context here is Backbone but it's a general question about dynamically creating javascript objects.

I would like to pass the name of a View ('ViewX') to be created, to a function which can then create the new ViewX()

How could I do this?

In my Backbone View I want to create a subView, the type of which depends on the Model I have used for the current View. At the moment I have an if-else structure (See Approach #1 in the example) which works, but is clunky and will be more clunky in future when I have more Model types.

I have tried some alternatives, including evaluation via the Function constructor (Approach #2), which gives 'string is not a function' error. In Approach #3, the View module I am passing as a parameter is not available in the current View's this namespace (I am using requirejs).

renderContentList: function() {

    var self = this;

    // Approach #1
    var setSidebarListCollectionView = function(type) {
       if (type === 'tags') {
           self.sidebarListCollectionView = new TagSidebarListCollectionView({
               collection: self.collection,
               tagCollection: self.tagCollection
           });
       } else {
           self.sidebarListCollectionView = new CardSidebarListCollectionView({
               collection: self.collection,
               tagCollection: self.tagCollection
           });
       }
    };
    /*
    // Approach #2
    var setSidebarListCollectionView = new Function('type', 'coll', 'tagColl', 'return new type({collection: coll, tagCollection: tagColl});');

    // Approach #3
    var setSidebarListCollectionView = function(type) {
        return new self[type]({
                        collection: self.collection,
                        tagCollection: self.tagCollection
                    });
    };
    */
    // reset it every time
    if (this.sidebarListCollectionView) {
        this.sidebarListCollectionView.remove();
    }
    if (this.model.get('activeSubTab') === 'tags') {
        // Approach #1
        setSidebarListCollectionView('tags');
        // Approach #2
        // this.sidebarListCollectionView = setSidebarListCollectionView('TagSidebarListCollectionView', this.collection, this.tagCollection);
        // Approach #3
        // this.sidebarListCollectionView = setSidebarListCollectionView('TagSidebarListCollectionView');
    } else {
        // Approach #1
        setSidebarListCollectionView('cards');
        // Approach #2
        // this.sidebarListCollectionView = setSidebarListCollectionView('CardSidebarListCollectionView', this.collection, this.tagCollection);
        // Approach #3
        // this.sidebarListCollectionView = setSidebarListCollectionView('CardSidebarListCollectionView');
    }

    // render the list of content title links.
    this.$el.find('#content-manager-list-content').append(this.sidebarListCollectionView.render().el);
},