一个代码设计模式的实现，action/reducer/dispatch

// 一定放在dispatch前面
const storeState = {
    todos: [
        { id: 695, text: '苏南大叔的日程1' },
        { id: 696, text: '苏南大叔的日程2' },
        { id: 697, text: '苏南大叔的日程3' }
    ]
};
const setTodos = (todos) => {
    storeState.todos = todos;
    console.log(storeState.todos);
}

function combineReducers(reducers) {
    return function reducer(state, action) {
        const changed = {};
        for (let key in reducers) {
            changed[key] = reducers[key](state[key], action);
        }
        return {
            ...state,
            ...changed,
        }
    };
}
const reducers = {
    todos(prevState, action) {
        const { type, payload } = action;
        switch (type) {
            case 'add':
                if (!prevState.find(todo => todo.text === payload.text)) {
                    return [...prevState, payload];
                }
                return prevState;
            case 'remove':
                return prevState.filter(todo => {
                    return todo.text !== payload.text;
                });
            default:
        }
        return prevState;
    },
};
const reducer = combineReducers(reducers);

const dispatch = (action) => {
    const setters = {
        todos: setTodos,
    }
    const newState = reducer(storeState, action);
    for (let key in newState) {
        setters[key](newState[key]);
    }
};

function createAdd(text) {
    return {
        type: 'add',
        payload: {
            id: parseInt(Date.now().toString().slice(-3)),
            text,
        },
    }
}
function createRemove(text) {
    return {
        type: 'remove',
        payload:{
            text
        }
    };
}

function bindActionCreators(actionCreators, dispatch) {
    const ret = {};
    for (let key in actionCreators) {
        ret[key] = function (...args) {
            const actionCreator = actionCreators[key];
            const action = actionCreator(...args);
            dispatch(action);
        };
    }
    return ret;
}

const obj = bindActionCreators({ addTodo: createAdd, removeTodo: createRemove }, dispatch);
obj.addTodo("苏南大叔在北京的行程");
obj.addTodo("苏南大叔在唐山的行程");
obj.removeTodo("苏南大叔的日程2");