code review

x-pack/plugins/graph/public/services/persistence/deserialize.ts

@@ -61,7 +61,13 @@ function deserializeUrlTemplate({
   return template;
 }
 
-// returns the id of the index pattern, lookup is done in app.js
+/**
+ * Migrates `savedWorkspace` to use the id instead of the title of the referenced index pattern.
+ * Returns a status indicating successful migration or failure to look up the index pattern by title.
+ * If the workspace is migrated already, a success status is returned as well.
+ * @param savedWorkspace The workspace saved object to migrate. The migration will happen in-place and mutate the passed in object
+ * @param indexPatterns All index patterns existing in the current space
+ */
 export function migrateLegacyIndexPatternRef(
   savedWorkspace: GraphWorkspaceSavedObject,
   indexPatterns: IndexPatternSavedObject[]
@@ -70,13 +76,13 @@ export function migrateLegacyIndexPatternRef(
   if (!legacyIndexPatternRef) {
     return { success: true };
   }
-  const serializedWorkspaceState: SerializedWorkspaceState = JSON.parse(savedWorkspace.wsState);
   const indexPatternId = indexPatterns.find(
     (pattern) => pattern.attributes.title === legacyIndexPatternRef
   )?.id;
   if (!indexPatternId) {
     return { success: false, missingIndexPattern: legacyIndexPatternRef };
   }
+  const serializedWorkspaceState: SerializedWorkspaceState = JSON.parse(savedWorkspace.wsState);
   serializedWorkspaceState.indexPattern = indexPatternId!;
   savedWorkspace.wsState = JSON.stringify(serializedWorkspaceState);
   delete savedWorkspace.legacyIndexPatternRef;