Fix showBlobInteractionZones throwing an error when no data exists

app/assets/javascripts/code_navigation/store/actions.js

@@ -30,7 +30,9 @@ export default {
     });
   },
   showBlobInteractionZones({ state }, path) {
-    Object.values(state.data[path]).forEach(d => addInteractionClass(path, d));
+    if (state.data && state.data[path]) {
+      Object.values(state.data[path]).forEach(d => addInteractionClass(path, d));
+    }
   },
   showDefinition({ commit, state }, { target: el }) {
     let definition;

spec/frontend/code_navigation/store/actions_spec.js

@@ -143,6 +143,16 @@ describe('Code navigation actions', () => {
       expect(addInteractionClass.mock.calls[0]).toEqual(['index.js', 'test']);
       expect(addInteractionClass.mock.calls[1]).toEqual(['index.js', 'console.log']);
     });
+
+    it('does not call addInteractionClass when no data exists', () => {
+      const state = {
+        data: null,
+      };
+
+      actions.showBlobInteractionZones({ state }, 'index.js');
+
+      expect(addInteractionClass).not.toHaveBeenCalled();
+    });
   });
 
   describe('showDefinition', () => {