https://github.com/rubydonkey/flux-todomvc-rails-51/blob/CRUD/app/javascript/todoApp/data/TodoErrorsStore.js

TodoErrorStore.js

'user strict'

import {ReduceStore} from 'flux/utils';

import TodoDispatcher from './TodoDispatcher';
import TodoActionTypes from './TodoActionTypes';

class TodoErrorsStore extends ReduceStore {
    constructor(){
        super(TodoDispatcher);
    }

    getInitialState(){
        return {
            add: {},
            edit: {},
        }
    }

    reduce(state, action){
        switch (action.type){
            case TodoActionTypes.ADD_TODO_ERROR:
                return ({
                    add: action.errors,
                    edit: {},
                });
            case TodoActionTypes.EDIT_TODO_ERROR:
                debugger;
                return ({
                    add: {},
                    edit: action.errors,
                });
            case TodoActionTypes.EDIT_TODO:
            case TodoActionTypes.UPDATE_DRAFT:
                return this.getInitialState();
            default:
                return state;
        }
    }
}

export default new TodoErrorsStore();