boardgame.io/src/plugins/plugin-immer.ts

library for turn-based games

/*
 * Copyright 2018 The boardgame.io Authors
 *
 * Use of this source code is governed by a MIT-style
 * license that can be found in the LICENSE file or at
 * https://opensource.org/licenses/MIT.
 */

import produce from 'immer';
import { AnyFn, Ctx, Plugin } from '../types';
import { INVALID_MOVE } from '../core/constants';

/**
 * Plugin that allows using Immer to make immutable changes
 * to G by just mutating it.
 */
const ImmerPlugin: Plugin = {
  name: 'plugin-immer',

  fnWrap: (move: AnyFn) => (G: any, ctx: Ctx, ...args: any[]) => {
    let isInvalid = false;
    const newG = produce(G, G => {
      const result = move(G, ctx, ...args);
      if (result === INVALID_MOVE) {
        isInvalid = true;
        return;
      }
      return result;
    });
    if (isInvalid) return INVALID_MOVE;
    return newG;
  },
};

export default ImmerPlugin;