immer-reducer-3.js

import produce, { applyPatches, enablePatches } from "immer";
enablePatches();

export const RESET = "RESET";
export const OPEN_DOOR = "OPEN_DOOR";
export const UNDO = "UNDO";

let inverseChanges = [];

export const reducer = (state, action) => {
  return produce(
    state,
    (draft) => {
      switch (action.type) {
        case OPEN_DOOR: {
          const { index } = action.payload;

          draft.doors[index].isOpen = true;
          break;
        }
        case RESET: {
          draft.doors = generateDoors();
          inverseChanges = [];
          break;
        }
        case UNDO: {
          if (inverseChanges.length > 0) {
            return applyPatches(state, [inverseChanges.pop()]);
          }
          break;
        }

        default:
          break;
      }
    },
    (patches, inversePatches) => {
      if (action.type === OPEN_DOOR) {
        inverseChanges.push(...inversePatches);
      }
    }
  );
};