Add action to change the fileByFile setting

app/assets/javascripts/diffs/constants.js

@@ -80,6 +80,8 @@ export const DIFF_FILE_MANUAL_COLLAPSE = 'manual';
 // Diff view single file mode
 export const DIFF_FILE_BY_FILE_COOKIE_NAME = 'fileViewMode';
 export const DIFF_VIEW_FILE_BY_FILE = 'single';
+export const DIFF_VIEW_ALL_FILES = 'all';
+
 // State machine states
 export const STATE_IDLING = 'idle';
 export const STATE_LOADING = 'loading';

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

@@ -44,6 +44,9 @@ import {
   EVT_PERF_MARK_FILE_TREE_START,
   EVT_PERF_MARK_FILE_TREE_END,
   EVT_PERF_MARK_DIFF_FILES_START,
+  DIFF_VIEW_FILE_BY_FILE,
+  DIFF_VIEW_ALL_FILES,
+  DIFF_FILE_BY_FILE_COOKIE_NAME,
 } from '../constants';
 import { diffViewerModes } from '~/ide/constants';
 import { isCollapsed } from '../diff_file';
@@ -57,6 +60,7 @@ export const setBaseConfig = ({ commit }, options) => {
     projectPath,
     dismissEndpoint,
     showSuggestPopover,
+    viewDiffsFileByFile,
   } = options;
   commit(types.SET_BASE_CONFIG, {
     endpoint,
@@ -66,6 +70,7 @@ export const setBaseConfig = ({ commit }, options) => {
     projectPath,
     dismissEndpoint,
     showSuggestPopover,
+    viewDiffsFileByFile,
   });
 };
 
@@ -694,3 +699,14 @@ export const navigateToDiffFileIndex = ({ commit, state }, index) => {
 
   commit(types.VIEW_DIFF_FILE, fileHash);
 };
+
+export const setFileByFile = ({ commit }, { fileByFile }) => {
+  const fileViewMode = fileByFile ? DIFF_VIEW_FILE_BY_FILE : DIFF_VIEW_ALL_FILES;
+  commit(types.SET_FILE_BY_FILE, fileByFile);
+
+  Cookies.set(DIFF_FILE_BY_FILE_COOKIE_NAME, fileViewMode);
+
+  historyPushState(
+    mergeUrlParams({ [DIFF_FILE_BY_FILE_COOKIE_NAME]: fileViewMode }, window.location.href),
+  );
+};

spec/frontend/diffs/store/actions_spec.js

@@ -48,6 +48,7 @@ import {
   moveToNeighboringCommit,
   setCurrentDiffFileIdFromNote,
   navigateToDiffFileIndex,
+  setFileByFile,
 } from '~/diffs/store/actions';
 import eventHub from '~/notes/event_hub';
 import * as types from '~/diffs/store/mutation_types';
@@ -1455,4 +1456,20 @@ describe('DiffsStoreActions', () => {
       );
     });
   });
+
+  describe('setFileByFile', () => {
+    it.each`
+      value
+      ${true}
+      ${false}
+    `('commits SET_FILE_BY_FILE with the new value $value', ({ value }) => {
+      return testAction(
+        setFileByFile,
+        { fileByFile: value },
+        { viewDiffsFileByFile: null },
+        [{ type: types.SET_FILE_BY_FILE, payload: value }],
+        [],
+      );
+    });
+  });
 });