Account type: Add a property featureLevel.

This adds a new property featureLevel in the type Account.
Consequently, we had to tweak loginSuccess() and realmAdd()
to include featureLevel in their return values.

Part of #4049.

Author: hashirsarwar

src/__tests__/lib/exampleData.js

@@ -122,6 +122,7 @@ export const makeAccount = (
     email?: string,
     realm?: string,
     apiKey?: string,
+    zulipFeatureLevel?: number | null,
     shouldHaveZulipVersion?: boolean,
     zulipVersion?: string,
     ackedPushToken?: string | null,
@@ -132,6 +133,7 @@ export const makeAccount = (
     email = user.email,
     realm: realmInner = realm,
     apiKey = randString() + randString(),
+    zulipFeatureLevel: zulipFeatureLevelInner = zulipFeatureLevel,
     shouldHaveZulipVersion = true,
     zulipVersion: zulipVersionInner = zulipVersion,
     ackedPushToken = null,
@@ -140,6 +142,7 @@ export const makeAccount = (
     realm: realmInner,
     email,
     apiKey,
+    zulipFeatureLevel: zulipFeatureLevelInner,
     zulipVersion: shouldHaveZulipVersion ? zulipVersionInner : undefined,
     ackedPushToken,
   });

src/account/__tests__/accountsReducer-test.js

@@ -31,6 +31,7 @@ describe('accountsReducer', () => {
         email: '',
         apiKey: '',
         realm: 'https://new.realm.org',
+        zulipFeatureLevel: null, // Will be removed in an upcoming commit.
       });
 
       const action = deepFreeze({
@@ -170,6 +171,7 @@ describe('accountsReducer', () => {
         email: '[email protected]',
         realm: 'https://new.realm.org',
         shouldHaveZulipVersion: false,
+        zulipFeatureLevel: null,
       });
 
       const action = deepFreeze({

src/account/accountsReducer.js

@@ -32,6 +32,7 @@ const realmAdd = (state, action) => {
       apiKey: '',
       email: '',
       ackedPushToken: null,
+      zulipFeatureLevel: null,
       zulipVersion: action.zulipVersion,
     },
     ...state,
@@ -65,7 +66,7 @@ const loginSuccess = (state, action) => {
   const { realm, email, apiKey } = action;
   const accountIndex = findAccount(state, { realm, email });
   if (accountIndex === -1) {
-    return [{ realm, email, apiKey, ackedPushToken: null }, ...state];
+    return [{ realm, email, apiKey, ackedPushToken: null, zulipFeatureLevel: null }, ...state];
   }
   return [
     { ...state[accountIndex], email, apiKey, ackedPushToken: null },

src/types.js

@@ -94,6 +94,20 @@ export type Account = {|
    */
   zulipVersion?: string,
 
+  /**
+   * An integer indicatating what features are available on the server.
+   *
+   * The feature level increases monotonically; a value of N means the
+   * server supports all API features introduced before feature level N.
+   * This is designed to provide a simple way for mobile apps to decide
+   * whether the server supports a given feature or API change.
+   *
+   * Like zulipVersion, we learn the feature level from /server_settings
+   * at the start of the login process, and again from /register when
+   * setting up an event queue.
+   */
+  zulipFeatureLevel: number | null,
+
   /**
    * The last device token value the server has definitely heard from us.
    *