redux-fluorine/es/util/wrapStateReducer.js

A Redux enhancer to manage groups of actions as observables (agendas)

import { RECOVER_AFTER_ERROR } from '../actions/filterActions';
import reapplyActionsWithout from './reapplyActionsWithout';

export default function wrapStateReducer(reducer, initialState) {
  if (typeof reducer !== 'function') {
    throw new Error('wrapStateReducer: Expected `reducer` to be a function.');
  }

  var _defaultState = {
    action: null,
    state: initialState,
    next: null
  };

  return function () {
    var state = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : _defaultState;
    var action = arguments[1];

    if (action.type === RECOVER_AFTER_ERROR) {
      // Reapply all past actions subtracting the errored ones
      var anchor = action.anchor;
      var actions = action.actions;

      return reapplyActionsWithout(reducer, anchor, actions);
    }

    var lastState = state.state;
    var nextState = reducer(lastState, action);

    // Create next wrapped state and link it
    state.next = {
      action: action,
      state: nextState,
      next: null
    };

    return state.next;
  };
}