Add a server sync status field (#307)

* Add a server sync status field

* tweak test to verify the public API as opposed to the internal field

Author: flungloaf

src/client/client.js

@@ -93,6 +93,7 @@ class _ClientImpl {
     this.credentials = credentials;
     this.multiplayer = multiplayer;
     this.subscribeCallback = () => {};
+    this.isSynced = false;
 
     this.reducer = CreateGameReducer({
       game,
@@ -176,6 +177,7 @@ class _ClientImpl {
 
         case Actions.SYNC: {
           this.log = action.log || [];
+          this.isSynced = true;
           break;
         }
       }
@@ -288,7 +290,7 @@ class _ClientImpl {
     const G = this.game.playerView(state.G, state.ctx, this.playerID);
 
     // Combine into return value.
-    let ret = { ...state, isActive, G, log: this.log };
+    let ret = { ...state, isActive, isSynced: this.isSynced, G, log: this.log };
 
     const isConnected = this.transport.isConnected;
     ret = { ...ret, isConnected };

src/client/client.test.js

@@ -49,6 +49,16 @@ test('isActive', () => {
   expect(client.getState().isActive).toBe(false);
 });
 
+test('isSynced', () => {
+  const client = Client({
+    game: Game({}),
+  });
+
+  expect(client.getState().isSynced).toBe(false);
+  client.store.dispatch(sync(client.getState(), []));
+  expect(client.getState().isSynced).toBe(true);
+});
+
 describe('step', () => {
   const client = Client({
     game: Game({