Example for Writing Better AngularJS Apps https://medium.com/p/f2ab70a104d0/

product-category-row.js

angular
  .module('app')
  .directive('productCategoryRow', productCategoryRow);
  
function productCategoryRow() {
  return {
    restrict: 'EA',
    scope: { title: '@productCategoryRow' },
    template: templateFn,
    controller: controllerFn,
    controllerAs: 'categoryCtrl',
    // So our isolated scope will be stored
    // on the ```this``` context of our controller
    // instead of $scope
    bindToController: true
  }
  
  function templateFn() {
    return [
      // Title
      // Minimize
      // Whatever
    ].join('');
  }
  
  function controllerFn($scope) {
    var vm = this;
    
    // Whatever..
  }
}

product-row.js

angular
  .module('app')
  .directive('productRow', productRow);
  
function productRow() {
  return {
    restrict: 'EA',
    scope: { data: '=productRow' },
    template: templateFn,
    controller: controllerFn,
    controllerAs: 'rowCtrl',
    // So our isolated scope will be stored
    // on the ```this``` context of our controller
    // instead of $scope
    bindToController: true
  }
  
  function templateFn() {
    return [
      // Product name
      // Whatever?
    ].join('');
  }
  
  function controllerFn($scope) {
    var vm = this;
    
    // Whatever..
  }
}

product-table.js

angular
  .module('app')
  .directive('productTable', productTable);
  
function productTable() {
  return {
    restrict: 'EA',
    scope: { filter: '@', data: '=productTable' },
    template: templateFn,
    controller: controllerFn,
    controllerAs: 'tableCtrl',
    // So our isolated scope will be stored
    // on the ```this``` context of our controller
    // instead of $scope
    bindToController: true
  }
  
  function templateFn() {
    return [
      '<section>',
        '<div ng-repeat="category in filtered() | filter: tableCtrl.filter " ng-if="!!category.products.length"> ',
          '<div product-row-header="{{ category.name }}"></div>',
          '<div ng-repeat="product in category.products" product-row="product"></div>',
        '</div>',
      '</div>'
    ].join('');
  }
  
  function controllerFn($scope) {
    var vm = this;
    var _categories = [];
    
    angular.extend(vm, { filtered: filtered });
    
    // I decided to use our own filter since
    // our data is kind of different
    function filtered() {
      // For first time use, let's get our headers.
      if ( !_categories.length ) {
        getCategories();
      }
      
      return _categories.map(function(category) {
        return vm.data.filter(function(product) { return category == product.category });
      });
    }
    
    function getCategories() {
      return vm.data.map(function(product) {
        if ( _categories.indexOf(product.category) !== -1 )
          return;
            
        _headers.push(property.category);
        return product.category;
      });
    }
  }
}

ProductController.js

// Our html would be,
// <product-search="productCtrl.filter"></product-table>
// <product-table="productCtrl.data"></product-table>

// Controller As productCtrl
angular
  .module('app')
  .controller('ProductController', ProductController);
  
function ProductController($scope, $http) {
  // If you are unfamiliar with this code style,
  // please check John Papa's or Todd Moto's Style Guide
  var vm = this;
  
  angular.extend(vm, { filter: '' });
  
  // Since this is an example,
  // I'd directly write an $http here.
  // Supposedly, you should ajax-calls wrap in a service
  $http.get('products.json')
    .then(function(response) { vm.data })
    .catch(function() { alert('An error has occured') });
}

products.json

[
  {category: "Sporting Goods", price: "$49.99", stocked: true, name: "Football"},
  {category: "Sporting Goods", price: "$9.99", stocked: true, name: "Baseball"},
  {category: "Sporting Goods", price: "$29.99", stocked: false, name: "Basketball"},
  {category: "Electronics", price: "$99.99", stocked: true, name: "iPod Touch"},
  {category: "Electronics", price: "$399.99", stocked: false, name: "iPhone 5"},
  {category: "Electronics", price: "$199.99", stocked: true, name: "Nexus 7"}
];

search-bar.js

angular
  .module('app')
  .directive('productSearchBar', productSearchBar);
  
function productSearchBar() {
  return {
    restrict: 'EA',
    scope: { filter: '=' },
    template: templateFn,
    controller: controllerFn,
    controllerAs: 'searchCtrl',
    // So our isolated scope will be stored
    // on the ```this``` context of our controller
    // instead of $scope
    bindToController: true
  }
  
  function templateFn() {
    return [
      // Input
    ].join('');
  }
  
  function controllerFn($scope) {
    var vm = this;
    
    // Whatever..
  }
}

Shouldn't your directives use .directive instead of .controller?

angular
  .module('app')
  .controller('productCategoryRow', productCategoryRow);

@tinyfly +1, I come here for pointing that too 😄

++ :)