Process only known moves (#151)

* allow a move to declare itself invalid by returning undefined

* don't process move that is unknown to the game

Author: Stefan-Hanke

src/core/game.test.js

@@ -25,6 +25,7 @@ test('basic', () => {
 test('processMove', () => {
   const testObj = { test: true };
   expect(game.processMove(testObj, { type: 'A' })).toEqual(testObj);
+  expect(game.processMove(testObj, { type: 'C' })).toEqual(testObj);
   expect(game.processMove(testObj, { type: 'B' })).toEqual(null);
 });
 

src/core/reducer.js

@@ -98,6 +98,11 @@ export function createGameReducer({ game, numPlayers, multiplayer }) {
       }
 
       case Actions.MAKE_MOVE: {
+        // check whether the game knows the move at all
+        if (!game.moveNames.includes(action.payload.type)) {
+          return state;
+        }
+
         // Ignore the move if it isn't valid at this point.
         if (!game.flow.canMakeMove(state.G, state.ctx, action.payload)) {
           return state;
@@ -109,6 +114,11 @@ export function createGameReducer({ game, numPlayers, multiplayer }) {
 
         // Process the move.
         let G = game.processMove(state.G, action.payload, ctxWithAPI);
+        if (G === undefined) {
+          // the game declared the move as invalid.
+          return state;
+        }
+
         // Update ctx with PRNG state.
         const ctx = random.update(state.ctx);
 

src/core/reducer.test.js

@@ -28,12 +28,25 @@ test('_stateID is incremented', () => {
 
   let state = undefined;
 
-  state = reducer(state, makeMove('unknown'));
+  state = reducer(state, makeMove('A'));
   expect(state._stateID).toBe(1);
   state = reducer(state, endTurn());
   expect(state._stateID).toBe(2);
 });
 
+test('when a move returns undef => treat as illegal move', () => {
+  const game = Game({
+    moves: {
+      A: G => undefined, // eslint-disable-line no-unused-vars
+    },
+  });
+  const reducer = createGameReducer({ game });
+
+  let state = reducer(state, makeMove('A'));
+
+  expect(state._stateID).toBe(0);
+});
+
 test('makeMove', () => {
   const reducer = createGameReducer({ game });
 
@@ -140,8 +153,8 @@ test('log', () => {
 
   let state = undefined;
 
-  const actionA = makeMove('moveA');
-  const actionB = makeMove('moveB');
+  const actionA = makeMove('A');
+  const actionB = makeMove('B');
   const actionC = endTurn();
 
   state = reducer(state, actionA);