Use Thema subjects.

app/controllers/PageCatalog.php

@@ -21,87 +21,7 @@ class PageCatalog extends Controller
 
     public function subjectGroups()
     {
-        return [
+        return \Pressbooks\Metadata\get_thema_subjects();
-            'business-finance' => [
-              'title' => __('Business and Finance', 'aldine'),
-              'subjects' => [
-                'accounting' => 'Accounting',
-                'finance' => 'Finance',
-                'information-systems' => 'Information Systems',
-                'management' => 'Management',
-                'marketing' => 'Marketing',
-                'economics' => 'Economics',
-              ],
-            ],
-            'engineering-technology' => [
-              'title' => __('Engineering & Technology', 'aldine'),
-              'subjects' => [
-                'architecture' => 'Architecture',
-                'bioengineering' => 'Bioengineering',
-                'chemical' => 'Chemical',
-                'civil' => 'Civil',
-                'electrical' => 'Electrical',
-                'mechanical' => 'Mechanical',
-                'mining-and-materials' => 'Mining and Materials',
-                'urban-planning' => 'Urban Planning',
-                'computer-science' => 'Computer Science',
-              ],
-            ],
-            'health-sciences' => [
-              'title' => __('Health Sciences', 'aldine'),
-              'subjects' => [
-                'nursing' => 'Nursing',
-                'dentistry' => 'Dentistry',
-                'medicine' => 'Medicine',
-              ],
-            ],
-            'humanities-arts' => [
-              'title' => __('Humanities & Arts', 'aldine'),
-              'subjects' => [
-                'archaeology' => 'Archaeology',
-                'art' => 'Art',
-                'classics' => 'Classics',
-                'literature' => 'Literature',
-                'history' => 'History',
-                'media' => 'Media',
-                'music' => 'Music',
-                'philosophy' => 'Philosophy',
-                'religion' => 'Religion',
-                'language' => 'Language',
-              ],
-            ],
-            'reference' => [
-              'title' => __('Reference', 'aldine'),
-              'subjects' => [
-                'student-guides' => 'Student Guides',
-                'teaching-guides' => 'Teaching Guides',
-              ],
-            ],
-            'science' => [
-              'title' => __('Sciences', 'aldine'),
-              'subjects' => [
-                'biology' => 'Biology',
-                'chemistry' => 'Chemistry',
-                'environent-and-earth-sciences' => 'Environment and Earth Sciences',
-                'geography' => 'Geography',
-                'mathematics' => 'Mathematics',
-                'physics' => 'Physics',
-              ],
-            ],
-            'social-sciences' => [
-              'title' => __('Social Sciences', 'aldine'),
-              'subjects' => [
-                'anthropology' => 'Anthropology',
-                'gender-studies' => 'Gender Studies',
-                'linguistics' => 'Linguistics',
-                'museums-libraries-and-information-sciences' => 'Museums, Libraries, and Information Sciences',
-                'political-science' => 'Political Science',
-                'psychology' => 'Psychology',
-                'social-work' => 'Social Work',
-                'sociology' => 'Sociology',
-              ],
-            ],
-        ];
     }
 
     public function catalogData()

resources/views/page-catalog.blade.php

@@ -16,10 +16,12 @@
         <div id="filter" class="filter-groups">
           @foreach($subject_groups as $key => $val)
           <div class="{{ $key }} subjects" id="{{ $key }}">
-            <a href="#{{ $key }}">{{ $val['title'] }} <svg class="arrow" width="13" height="8" viewBox="0 0 13 8" xmlns="http://www.w3.org/2000/svg"><path d="M6.255 8L0 0h12.51z" fill="#b01109" fill-rule="evenodd"/></svg></a>
+            <a href="#{{ $key }}">{{ $val['label'] }} <svg class="arrow" width="13" height="8" viewBox="0 0 13 8" xmlns="http://www.w3.org/2000/svg"><path d="M6.255 8L0 0h12.51z" fill="#b01109" fill-rule="evenodd"/></svg></a>
             <ul class="filter-list">
-              @foreach($val['subjects'] as $k => $v)
+              @foreach($val['children'] as $k => $v)
+              @if(strlen($k) === 2)
                 <li><a data-filter="{{ $k }}">{{ $v }}<span class="close">&times;</span></a></li>
+              @endif
               @endforeach
             </ul>
           </div>