Management sections: Allow easy sub-section lookup (#10651)

* Allow sub-section lookup using `/` separator

* Adding assertion to check against the more explicit method

* Conforming to JS style guide

* Better wording

src/ui/public/management/__tests__/section.js

@@ -94,6 +94,16 @@ describe('ManagementSection', () => {
     it('returns undefined if un-registered', () => {
       expect(section.getSection('unknown')).to.be(undefined);
     });
+
+    it('returns sub-sections specified via a /-separated path', () => {
+      section.getSection('about').register('time');
+      expect(section.getSection('about/time')).to.be.a(ManagementSection);
+      expect(section.getSection('about/time')).to.be(section.getSection('about').getSection('time'));
+    });
+
+    it('returns undefined if a sub-section along a /-separated path does not exist', () => {
+      expect(section.getSection('about/damn/time')).to.be(undefined);
+    });
   });
 
   describe('items', () => {

src/ui/public/management/section.js

@@ -72,6 +72,17 @@ export default class ManagementSection {
    */
 
   getSection(id) {
-    return this.items.byId[id];
+    if (!id) {
+      return;
+    }
+
+    const sectionPath = id.split('/');
+    return sectionPath.reduce((currentSection, nextSection) => {
+      if (!currentSection) {
+        return;
+      }
+
+      return currentSection.items.byId[nextSection];
+    }, this);
   }
 }