Only show left sidebar toggle if there is a sidebar

Summary:
^

Not all selections have a left sidebar. If the current selection doesn't have one, it doesn't make sense to have the toggle sidebar button, so hide it.

Reviewed By: LukeDefeo

Differential Revision: D47593545

fbshipit-source-id: 940d59536e26bd1ab341d2038df431c67e0a5442

desktop/flipper-ui-core/src/reducers/application.tsx

@@ -37,6 +37,7 @@ export type ShareType = {
 } & SubShareType;
 
 export type State = {
+  hasLeftSidebar: boolean;
   leftSidebarVisible: boolean;
   rightSidebarVisible: boolean;
   rightSidebarAvailable: boolean;
@@ -48,6 +49,7 @@ export type State = {
 };
 
 type BooleanActionType =
+  | 'hasLeftSidebar'
   | 'leftSidebarVisible'
   | 'rightSidebarVisible'
   | 'rightSidebarAvailable';
@@ -78,6 +80,7 @@ export type Action =
     };
 
 export const initialState: () => State = () => ({
+  hasLeftSidebar: true,
   leftSidebarVisible: true,
   rightSidebarVisible: true,
   rightSidebarAvailable: false,
@@ -110,6 +113,7 @@ export default function reducer(
 ): State {
   state = state || initialState();
   if (
+    action.type === 'hasLeftSidebar' ||
     action.type === 'leftSidebarVisible' ||
     action.type === 'rightSidebarVisible' ||
     action.type === 'rightSidebarAvailable'
@@ -175,6 +179,11 @@ export const toggleLeftSidebarVisible = (payload?: boolean): Action => ({
   payload,
 });
 
+export const toggleHasLeftSidebar = (payload?: boolean): Action => ({
+  type: 'hasLeftSidebar',
+  payload,
+});
+
 export const toggleRightSidebarVisible = (payload?: boolean): Action => ({
   type: 'rightSidebarVisible',
   payload,