Support appending a category id to a navigation item dynamically

app/assets/javascripts/discourse/components/navigation-item.js.es6

@@ -16,7 +16,18 @@ export default Ember.Component.extend(bufferedRender({
 
   buildBuffer(buffer) {
     const content = this.get('content');
-    buffer.push("<a href='" + content.get('href') + "'>");
+
+    let href = content.get('href');
+
+    // Include the category id if the option is present
+    if (content.get('includeCategoryId')) {
+      let categoryId = this.get('category.id');
+      if (categoryId) {
+        href += `?category_id=${categoryId}`;
+      }
+    }
+
+    buffer.push(`<a href='${href}'>`);
     if (content.get('hasIcon')) {
       buffer.push("<span class='" + content.get('name') + "'></span>");
     }

app/assets/javascripts/discourse/templates/components/navigation-bar.hbs

@@ -1,5 +1,5 @@
 {{#each navItems as |navItem|}}
-  {{navigation-item content=navItem filterMode=filterMode}}
+  {{navigation-item content=navItem filterMode=filterMode category=category}}
 {{/each}}
 {{custom-html name="extraNavItem" tagName="li"}}
 {{!- this is done to avoid DIV in the UL, originally {{plugin-outlet name="extra-nav-item"}}

app/assets/javascripts/discourse/templates/mobile/components/navigation-bar.hbs

@@ -7,7 +7,7 @@
 {{#if expanded}}
 <ul class='drop'>
   {{#each navItems as |navItem|}}
-    {{navigation-item content=navItem filterMode=filterMode}}
+    {{navigation-item content=navItem filterMode=filterMode category=category}}
   {{/each}}
 </ul>
 {{/if}}