add playerSetup option to PluginPlayer

This is a new field in the game object that is used to
determine the initial player states (as opposed to a
parameter that was passed to PluginPlayer itself). As
a result, PluginPlayer is now an actual plugin object (as opposed
to a function that returns a plugin).

docs/plugins.md

@@ -80,12 +80,9 @@ that they are specified (from left to right).
 ```js
 import { PluginPlayer } from 'boardgame.io/plugins';
 
-function PlayerState(playerID) {
-  return { ... };
-}
-
 Game({
-  plugins: [PluginPlayer(PlayerState)],
+  playerSetup: (playerID) => ({ ... }),
+  plugins: [PluginPlayer],
 })
 ```
 
@@ -104,9 +101,7 @@ G: {
 }
 ```
 
-The initial values of these states are determined by the parameter
-`PlayerState`, which is a function that returns the state for a
-particular `playerID`.
+The initial values of these states are determined by the `playerSetup` function, which creates the state for a particular `playerID`.
 
 Before each move, the plugin makes the state associated with the
 current player available at `G.player`. If this is a 2 player game,

src/plugins/plugin-player.js

@@ -13,7 +13,7 @@
  *
  * @param {function} initPlayerState - Function of type (playerID) => playerState.
  */
-export default initPlayerState => ({
+export default {
   fnWrap: moveFn => {
     return (G, ctx, ...args) => {
       const current = ctx.currentPlayer;
@@ -49,16 +49,16 @@ export default initPlayerState => ({
   },
 
   G: {
-    setup: (G, ctx) => {
+    setup: (G, ctx, game) => {
       let players = {};
       for (let i = 0; i < ctx.numPlayers; i++) {
-        const playerState = {};
-        if (initPlayerState !== undefined) {
-          initPlayerState(i + '');
+        let playerState = {};
+        if (game.playerSetup !== undefined) {
+          playerState = game.playerSetup(i + '');
         }
         players[i + ''] = playerState;
       }
       return { ...G, players };
     },
   },
-});
+};

src/plugins/plugin-player.test.js

@@ -13,8 +13,22 @@ import { makeMove, gameEvent } from '../core/action-creators';
 
 describe('default values', () => {
   test('playerState is not passed', () => {
-    const value = PluginPlayer().G.setup({}, { numPlayers: 2 });
-    expect(value).toEqual({ players: { '0': {}, '1': {} } });
+    const game = Game({
+      plugins: [PluginPlayer],
+    });
+    const reducer = CreateGameReducer({ game });
+    const state = reducer(undefined, { type: 'init' });
+    expect(state.G).toEqual({ players: { '0': {}, '1': {} } });
+  });
+
+  test('playerState is passed', () => {
+    const game = Game({
+      playerSetup: () => ({ A: 1 }),
+      plugins: [PluginPlayer],
+    });
+    const reducer = CreateGameReducer({ game });
+    const state = reducer(undefined, { type: 'init' });
+    expect(state.G).toEqual({ players: { '0': { A: 1 }, '1': { A: 1 } } });
   });
 });
 
@@ -32,7 +46,7 @@ describe('2 player game', () => {
         },
       },
 
-      plugins: [PluginPlayer(() => ({}))],
+      plugins: [PluginPlayer],
     });
 
     reducer = CreateGameReducer({ game });
@@ -75,7 +89,7 @@ describe('3 player game', () => {
         },
       },
 
-      plugins: [PluginPlayer()],
+      plugins: [PluginPlayer],
     });
 
     reducer = CreateGameReducer({ game, numPlayers: 3 });