从另一个减速器内的一个减速器访问减速器状态的一部分

Question

我不知道如何isLoading从reducerForm.jsreducer中访问一个布尔标志reducerRegister.js.我已经使用过combineReducers(),我isLoading在表单提交过程中用来禁用按钮.

它的初始状态为false,点击提交后,它会变为true.表单提交成功后,再次isLoading重置false.以下是此问题的相关代码:

actionRegister.js

let _registerUserFailure = (payload) => {
    return {
        type: types.SAVE_USER_FAILURE,
        payload
    };
};
let _registerUserSuccess = (payload) => {
    return {
        type: types.SAVE_USER_SUCCESS,
        payload,
        is_Active: 0,
        isLoading:true
    };
};

let _hideNotification = (payload) => {
    return {
        type: types.HIDE_NOTIFICATION,
        payload: ''
    };
};

// asynchronous helpers
export function registerUser({ // use redux-thunk for asynchronous dispatch
    timezone,
    password,
    passwordConfirmation,
    email,
    name
}) {
    return dispatch => {
        axios.all([axios.post('/auth/signup', {
                    timezone,
                    password,
                    passwordConfirmation,
                    email,
                    name,
                    is_Active: 0
                })
                // axios.post('/send', {email})
            ])
            .then(axios.spread(res => {
                dispatch(_registerUserSuccess(res.data.message));
                dispatch(formReset());
                setTimeout(() => {
                    dispatch(_hideNotification(res.data.message));
                }, 10000);
            }))
            .catch(res => {
                // BE validation and passport error message
                dispatch(_registerUserFailure(res.data.message));
                setTimeout(() => {
                    dispatch(_hideNotification(res.data.message));
                }, 10000);
            });
    };
} 

actionForm.js

export function formUpdate(name, value)  {
    return {
        type: types.FORM_UPDATE_VALUE,
        name, //shorthand from name:name introduced in ES2016
        value
    };
}
export function formReset() {
  return {
    type: types.FORM_RESET
  };
}

reducerRegister.js

const INITIAL_STATE = {
  error:{},
  is_Active:false,
  isLoading:false
};
const reducerSignup = (state = INITIAL_STATE , action) => {
  switch(action.type) {
    case types.SAVE_USER_SUCCESS:
      return { ...state, is_Active:false, isLoading: true, error: { register: action.payload }};
      case types.SAVE_USER_FAILURE:
      return { ...state, error: { register: action.payload }};
      case types.HIDE_NOTIFICATION:
      return { ...state , error:{} };
   }
      return state;
};
export default reducerSignup;

reducerForm.js

const INITIAL_STATE = {
    values: {}
};
const reducerUpdate = (state = INITIAL_STATE, action) => {
    switch (action.type) {
        case types.FORM_UPDATE_VALUE:
            return Object.assign({}, state, {
                values: Object.assign({}, state.values, {
                    [action.name]: action.value,
                })
            });
        case types.FORM_RESET:
        return INITIAL_STATE;
        // here I need isLoading value from reducerRegister.js
    }
    return state;
};
export default reducerUpdate;

reducerCombined.js

import { combineReducers } from 'redux';
import reducerRegister from './reducerRegister';
import reducerLogin from './reducerLogin';
import reducerForm from './reducerForm';

const rootReducer = combineReducers({
  signup:reducerRegister,
  signin: reducerLogin,
  form: reducerForm
});

export default rootReducer;

这是我使用的地方isLoading:

  let isLoading = this.props.isLoading;
<FormGroup>
    <Col smOffset={4} sm={8}>
     <Button type="submit"  disabled={isLoading}
       onClick={!isLoading ? isLoading : null}
     >
     { isLoading ? 'Creating...' : 'Create New Account'}
       </Button>
   </Col>
       </FormGroup>

将状态映射到同一组件中的props

function mapStateToProps(state) {
    return {
        errorMessage: state.signup.error,
    isLoading: state.signup.isLoading,
    values: state.form.values

    };
}

Answer 1

这在http://redux.js.org/docs/faq/Reducers.html#reducers-share-state上的Redux FAQ中有所介绍:

许多用户后来想尝试在两个reducers之间共享数据,但发现combineReducers不允许他们这样做.有几种方法可以使用:

• 如果reducer需要知道来自另一个状态切片的数据,则可能需要重新组织状态树形状,以便单个reducer处理更多数据.
• 您可能需要编写一些自定义函数来处理其中一些操作.这可能需要将combineReducers替换为您自己的顶级reducer功能.您还可以使用reduce-reducers等实用程序来运行combineReducers来处理大多数操作,还可以为跨越状态切片的特定操作运行更专业的reducer.
• 异步操作创建程序(如redux-thunk)可以通过getState()访问整个状态.操作创建者可以从状态检索其他数据并将其放入操作中,以便每个reducer都有足够的信息来更新其自己的状态切片.

Answer 2

reducer无法访问另一个reducer的状态,但是如果你正在使用redux-thunk,你可以在一个动作创建者中这样做.例如,您可以定义这样的动作创建者:

export const someAction = () =>
  (dispatch, getState) => {
    const someVal = getState().someReducer.someVal;
    dispatch({ type: types.SOME_ACTION, valFromOtherReducer: someVal });
  };

Answer 3

React Redux适用于单向数据流.

Action ---> Reducer /store ---> Reducer

Reducer适用于小商店的子集,你不能访问不属于Reducer的reducer里面的商店.您可能需要根据reducer状态返回从组件中触发新操作.