session [nfc]: Refactor to use RESET_ACCOUNT_DATA

Related: zulip#4446

Author: chrisbobbe

src/session/__tests__/sessionReducer-test.js

@@ -3,7 +3,6 @@ import deepFreeze from 'deep-freeze';
 
 import {
   DEAD_QUEUE,
-  LOGOUT,
   APP_ONLINE,
   REGISTER_ABORT,
   APP_ORIENTATION,
@@ -19,18 +18,22 @@ import * as eg from '../../__tests__/lib/exampleData';
 describe('sessionReducer', () => {
   const baseState = eg.baseReduxState.session;
 
-  test('ACCOUNT_SWITCH', () => {
-    const state = deepFreeze({
-      ...baseState,
-      loading: true,
-    });
-    const newState = sessionReducer(state, eg.action.account_switch);
-    expect(newState).toEqual({ ...baseState, ...initialPerAccountSessionState });
-  });
+  describe('RESET_ACCOUNT_DATA', () => {
+    test('resets per-account state without touching global state', () => {
+      const prevState = [
+        // per-account
+        eg.action.register_complete,
+        { type: DISMISS_SERVER_COMPAT_NOTICE },
 
-  test('LOGIN_SUCCESS', () => {
-    const newState = sessionReducer(baseState, eg.action.login_success);
-    expect(newState).toEqual({ ...baseState, ...initialPerAccountSessionState });
+        // global
+        { type: GOT_PUSH_TOKEN, pushToken: '456' },
+        { type: APP_ORIENTATION, orientation: 'LANDSCAPE' },
+      ].reduce(sessionReducer, eg.baseReduxState.session);
+      expect(sessionReducer(prevState, eg.action.reset_account_data)).toEqual({
+        ...prevState,
+        ...initialPerAccountSessionState,
+      });
+    });
   });
 
   test('DEAD_QUEUE', () => {
@@ -39,18 +42,6 @@ describe('sessionReducer', () => {
     expect(newState).toEqual({ ...baseState, loading: false });
   });
 
-  test('LOGOUT', () => {
-    const state = deepFreeze({
-      ...baseState,
-      loading: true,
-    });
-    const newState = sessionReducer(state, deepFreeze({ type: LOGOUT }));
-    expect(newState).toEqual({
-      ...baseState,
-      ...initialPerAccountSessionState,
-    });
-  });
-
   test('REGISTER_COMPLETE', () => {
     const state = deepFreeze({ ...baseState, loading: true });
     const action = eg.mkActionRegisterComplete({ queue_id: '100' });

src/session/sessionReducer.js

@@ -3,17 +3,15 @@ import type { Debug, Orientation, Action } from '../types';
 import {
   REHYDRATE,
   DEAD_QUEUE,
-  LOGIN_SUCCESS,
+  RESET_ACCOUNT_DATA,
   APP_ONLINE,
-  ACCOUNT_SWITCH,
   REGISTER_START,
   REGISTER_ABORT,
   REGISTER_COMPLETE,
   APP_ORIENTATION,
   TOGGLE_OUTBOX_SENDING,
   DEBUG_FLAG_TOGGLE,
   GOT_PUSH_TOKEN,
-  LOGOUT,
   DISMISS_SERVER_COMPAT_NOTICE,
 } from '../actionConstants';
 
@@ -154,41 +152,15 @@ export default (state: SessionState = initialState, action: Action): SessionStat
         eventQueueId: null,
       };
 
-    case LOGIN_SUCCESS:
+    case RESET_ACCOUNT_DATA:
       return {
         ...state,
-        loading: false,
-        outboxSending: false,
-        hasDismissedServerCompatNotice: false,
-
-        // We're about to request a new event queue; no use hanging on to
-        // any old one we might have.
-        eventQueueId: null,
-      };
-
-    case LOGOUT:
-      return {
-        ...state,
-        loading: false,
-        outboxSending: false,
-        hasDismissedServerCompatNotice: false,
 
-        // Stop polling this event queue.
-        eventQueueId: null,
-      };
-
-    case ACCOUNT_SWITCH:
-      return {
-        ...state,
-        loading: false,
-        outboxSending: false,
-        hasDismissedServerCompatNotice: false,
-
-        // Stop polling this event queue.  (We'll request a new one soon,
-        // for the new account.)
-        // TODO(#5005): Keep polling on accounts other than the active
-        //   account.
-        eventQueueId: null,
+        // Clear per-account session state. Importantly, stop polling on the
+        // account's current event queue if we had one. In the polling loop,
+        // after each server response, we check if we've dropped the queue
+        // ID from this state and break out if so.
+        ...initialPerAccountSessionState,
       };
 
     case REHYDRATE: