Rely on URL paths when choosing among multiple indices

src/utils/navigatorData.js

@@ -179,16 +179,21 @@ export function getSiblings(uid, childrenMap, children) {
 }
 
 function extractRootNode(data) {
+  // note: this "root" path won't always necessarily come at the beginning of
+  // the URL in situations where the renderer is being hosted at some path
+  // prefix
+  const rootPathPattern = /^.*(\/documentation\/[^/]+).*$/;
+  const rootPath = window.location.href.match(rootPathPattern)?.[1] ?? '';
   // most of the time, it is expected that `data` always has a single item
   // that represents the top-level root node of the navigation tree
   //
   // there may be rare, unexpected scenarios where multiple top-level root
-  // nodes are provide for some reason—if that happens, we would prefer the
-  // first one categorized as a "module"
+  // nodes are provide for some reason—if that happens, we would prefer the one
+  // with a path that most closely resembles the current URL path
   //
   // otherwise, the first provided node will be used
   return data.length === 1 ? data[0] : (data.find(node => (
-    node.type === TopicTypes.module
+    node.path.toLowerCase() === rootPath.toLowerCase()
   )) ?? data[0]);
 }
 

tests/unit/utils/navigatorData.spec.js

@@ -359,7 +359,11 @@ describe('when multiple top-level children are provided', () => {
   };
 
   describe('flattenNavigationIndex', () => {
-    it('prefers modules', () => {
+    it('prefers the root child with the same url path prefix', () => {
+      Object.defineProperty(window, 'location', {
+        value: { href: 'http://localhost/documentation/b/b42' },
+      });
+
       // use first root node if only one is provided
       let flattenedIndex = flattenNavigationIndex({ swift: [a] });
       expect(flattenedIndex.swift.length).toBe(1);
@@ -368,7 +372,7 @@ describe('when multiple top-level children are provided', () => {
       expect(flattenedIndex.swift.length).toBe(1);
       expect(flattenedIndex.swift[0].title).toBe(b.children[0].title);
 
-      // prefer "module" root when multiple top-level nodes are provided
+      // prefers root node with same url path prefix when multiple are provided
       flattenedIndex = flattenNavigationIndex({ swift: [a, b] });
       expect(flattenedIndex.swift.length).toBe(1);
       expect(flattenedIndex.swift[0].title).toBe(b.children[0].title);
@@ -388,14 +392,18 @@ describe('when multiple top-level children are provided', () => {
   });
 
   describe('extractTechnologyProps', () => {
-    it('prefers modules', () => {
+    it('prefers the root child with the same url path prefix', () => {
+      Object.defineProperty(window, 'location', {
+        value: { href: 'http://localhost/documentation/b/b42' },
+      });
+
       // use first root node if only one is provided
       let props = extractTechnologyProps({ swift: [a] });
       expect(props.swift.technology).toBe(a.title);
       props = extractTechnologyProps({ swift: [b] });
       expect(props.swift.technology).toBe(b.title);
 
-      // prefer "module" root when multiple top-level nodes are provided
+      // prefers root node with same url path prefix when multiple are provided
       props = extractTechnologyProps({ swift: [a, b] });
       expect(props.swift.technology).toBe(b.title);