How to handle conditional sub-category in AngularJS product gallery -

just starting out learning angularjs , decided mock basic product gallery using i've learned far , i've hit roadblock. have simple product gallery 3 templates(category listing, products in category listing , product overview). set sort of conditional, if products in selected category have sub-category, displays list of sub-categories using category-list template. if don't have sub-category goes straight product-list template.

i have created plunker showing @ far.

in above example, if clicks on "cars" want show listing of sub-categories using category-list template. when click "cars" take screen 2 buttons: 4-door , 2-door. clicking on 1 of buttons show products sub-categories using product-list template. however, if click on "trucks" initial screen, take directly product-list template since trucks don't have sub-categories.

here category-list template:

<section id="categories" ng-hide="productsvisible">     <div ng-repeat="product in vm.products" class="category">         <div ng-click="vm.selectcategory(product); showproducts();">             <button>{{product.category}}</button>         </div>     </div> </section> 

and here product-list template:

<section id="products" ng-show="productsvisible">     <div ng-repeat="product in vm.selectedcategory.items" class="product">         <a href ng-click="vm.selectproduct(product); showresults();">{{product.name}}</a>     </div> </section> 

see updated plunker

basically, need extend selectcategory method grouping sub-categories , checking whether we're enter sub-category in subsequent click. this:

vm.selectcategory = function(category) {   var subcats = [],       map = {};    if (category.items && !category.items[0].subcategory){     vm.selectedcategory = category;     vm.insubcat = true;     return;   }    vm.insubcat = !category.items;   if (category.items) category.items.foreach(function(e){     if (!map[e.subcategory]) subcats.push({category: e.subcategory, name: category.category});     map[e.subcategory] = true;   });   vm.products = subcats;    if (vm.insubcat) vm.selectedcategory = {items: vm.data.filter(function(c){     return c.category == category.name;   })[0].items.filter(function(p){     return p.subcategory == category.category;   }) }; }