Add a mutation to set the MR Metadata into state

app/assets/javascripts/mr_notes/stores/modules/index.js

@@ -6,6 +6,7 @@ export default () => ({
   state: {
     endpoints: {},
     activeTab: null,
+    mrMetadata: {},
   },
   actions,
   getters,

app/assets/javascripts/mr_notes/stores/mutation_types.js

 export default {
   SET_ACTIVE_TAB: 'SET_ACTIVE_TAB',
   SET_ENDPOINTS: 'SET_ENDPOINTS',
+  SET_MR_METADATA: 'SET_MR_METADATA',
 };

app/assets/javascripts/mr_notes/stores/mutations.js

@@ -7,4 +7,7 @@ export default {
   [types.SET_ENDPOINTS](state, endpoints) {
     Object.assign(state, { endpoints });
   },
+  [types.SET_MR_METADATA](state, metadata) {
+    Object.assign(state, { mrMetadata: metadata });
+  },
 };

spec/frontend/mr_notes/stores/mutations_spec.js

@@ -12,4 +12,16 @@ describe('MR Notes Mutations', () => {
       expect(state.endpoints).toEqual(endpoints);
     });
   });
+
+  describe(mutationTypes.SET_MR_METADATA, () => {
+    it('store the provided MR Metadata in the state', () => {
+      const state = {};
+      const metadata = { propA: 'A', propB: 'B' };
+
+      mutations[mutationTypes.SET_MR_METADATA](state, metadata);
+
+      expect(state.mrMetadata.propA).toBe('A');
+      expect(state.mrMetadata.propB).toBe('B');
+    });
+  });
 });