fix(traverseschema.js): skip generating files for certain keywords in…

… the schema

When traversing the schemas, some objects and arrays are misinterpreted as schemas to be documented
rather than as generic structures used to define the schemas. Namely: 'examples', 'required', and
'properties'. Including these structures in the loadedschemas list generates a number of extranious
files with little value to the generated documentation.

BREAKING CHANGE: The extranious files, if they have some other value, will not be generated and
there is no mechanism to continue to g

lib/traverseSchema.js

@@ -10,24 +10,45 @@
  * governing permissions and limitations under the License.
  */
 
-const { list } = require('ferrum');
+const { list, eq } = require('ferrum');
 const { parent } = require('./symbols');
 
+function isSkippable(schema, keyword) {
+  if (typeof schema[parent] !== 'object') {
+    return false;
+  }
+  if (!Object.keys(schema[parent]).includes(keyword)) {
+    return false;
+  }
+  const skippableSchema = JSON.parse(JSON.stringify(schema[parent][keyword]));
+  const currentSchema = JSON.parse(JSON.stringify(schema));
+
+  return eq(skippableSchema, currentSchema);
+}
+
 function reducer({ seen, ids }, schema) {
   if (schema
     && schema[parent]
     && (seen.has(schema) || (schema.$id && ids.indexOf(schema.$id) >= 0))) {
     return { seen, ids };
   } else if (Array.isArray(schema)) {
+    if (isSkippable(schema, 'examples')) {
+      return { seen, ids };
+    }
+    if (isSkippable(schema, 'required')) {
+      return { seen, ids };
+    }
     return schema.reduce(reducer, { seen, ids });
   } else if (schema && typeof schema === 'object') {
+    if (isSkippable(schema, 'properties')) {
+      return [...Object.values(schema)].reduce(reducer, { seen, ids });
+    }
     seen.add(schema);
     if (schema.$id) {
       ids.push(schema.$id);
     }
     return [...Object.values(schema)].reduce(reducer, { seen, ids });
   }
-
   return { seen, ids };
 }