无法使用 combine reducer REACT 显示数据

Question

without redux it works so that not a api connection problem

我有一个连接到代理的快速应用程序我已经设法在 React 中显示我的数据，但现在我想在 redux 中制作它 soo:

这是我的问题，我已经制作了所有 reducers/action、store 和 combine reducer，但是 我没有在我的页面中看到任何数据 我没有任何错误

这是我的代码：

Action

export const api = ext => `http://localhost:8080/${ext}`;

//
// ─── ACTION TYPES ───────────────────────────────────────────────────────────────
//

export const GET_ADVERTS = "GET_ADVERTS";
export const GET_ADVERT = "GET_ADVERT";

//
// ─── ACTION CREATORS ────────────────────────────────────────────────────────────
//

export function getAdverts() {
  return dispatch => {
    fetch("adverts")
      .then(res => res.json())
      .then(payload => {
        dispatch({ type: GET_ADVERTS, payload });
      });
  };
}

export function getAdvert(id) {
  return dispatch => {
    fetch(`adverts/${id}`)
      .then(res => res.json())
      .then(payload => {
        dispatch({ type: GET_ADVERT, payload });
      });
  };
}

reducer

import { combineReducers } from "redux";
import { GET_ADVERTS, GET_ADVERT } from "../actions/actions";
const INITIAL_STATE = {
  adverts: [],
  advert: {}
};

function todos(state = INITIAL_STATE, action) {
  switch (action.type) {
    case GET_ADVERTS:
      return { ...state, adverts: action.payload };
    case GET_ADVERT:
      return { advert: action.payload };
    default:
      return state;
  }
}

const todoApp = combineReducers({
  todos
});

export default todoApp;

index.js

//imports
const store = createStore(todoApp, applyMiddleware(thunk));

ReactDOM.render(
  <Provider store={store}>
    <BrowserRouter>
      <App />
    </BrowserRouter>
  </Provider>,

  document.getElementById("app")
);

My advertlist page :

//imports..

class Adverts extends Component {


  componentDidMount() {
    this.props.getAdverts();
  }

  render() {
    const { adverts = [] } = this.props;

    return (
      <div>
        <Header />
        <h1>Adverts</h1>
        {adverts.map(advert => (
          <li key={advert._id}>
            <a href={"adverts/" + advert._id}>
              {advert.name} {advert.surname}
            </a>
          </li>
        ))}

        <Footer />
      </div>
    );
  }
}

const mapStateToProps = state => ({
  adverts: state.adverts
});

export default connect(
  mapStateToProps,
  { getAdverts }
)(Adverts);

Answer 1

我认为你的问题出在这里：

function mapStateToProps(state) {
  return {
    **adverts: state.adverts**
  };
}

如果您 将 state.adverts 更改为 state.todos.adverts:

，它应该会起作用

function mapStateToProps(state) {
  return {
    adverts: state.todos.adverts
  };
}

因为你的 reducer 叫做 todos，它有状态 { adverts }，这就是为什么你不能访问广告，即使它们已经被获取。

您可以在此处查看工作版本：https://codesandbox.io/s/olqxm4mkpq

Answer 2

问题是，当你只用一个 reducer 创建一个 store 而不使用 combine reducer 时，可以直接在 ContainerS 中引用它，就像这样：

const mapStateToProps = state => {
    
    return{
        *name of var*:  state.adverts   /*direct refers to adverts*/
    }
}

但是，当它使用 combined-reducer 时，它必须引用您想要 use.like 的确切减速器：

const mapStateToProps = state => {
    
    return{
        *name of var* :  state.todos.adverts   (indirect refers to adverts from combined-reducer todos)
    }
}

无法使用 combine reducer REACT 显示数据

Can't display data using combine reducer REACT

javascript

action

reducers

node.js

reactjs