build(docs-infra): improve directive API doc templates (#25768)

Closes #22790
Closes #25530

PR Close #25768

aio/tools/transforms/angular-base-package/rendering/hasValues.js

@@ -3,7 +3,21 @@ module.exports = function hasValues() {
     name: 'hasValues',
     process: function(list, property) {
       if (!list || !Array.isArray(list)) return false;
-      return list.some(item => item[property]);
+      return list.some(item => readProperty(item, property.split('.'), 0));
     }
   };
-};
+};
+
+/**
+ * Search deeply into an object via a collection of property segments, starting at the
+ * indexed segment.
+ *
+ * E.g. if `obj = { a: { b: { c: 10 }}}` then
+ *  `readProperty(obj, ['a', 'b', 'c'], 0)` will return true;
+ * but
+ *  `readProperty(obj, ['a', 'd'], 0)` will return false;
+ */
+function readProperty(obj, propertySegments, index) {
+  const value = obj[propertySegments[index]];
+  return !!value && (index === propertySegments.length - 1 || readProperty(value, propertySegments, index + 1));
+}