Redux 动作调度不起作用

IT技术 javascript reactjs redux redux-thunk
2021-05-19 16:31:29

我试图在用户提交表单时分派一个动作。假设我有一个提交按钮，它会触发onSubmit表单上的一个事件（最终会在处理表单请求时显示一个微调图标，但此时，提交按钮只显示一个true或false值，表示微调是否正在显示）。

登录页面.js

import React from 'react';
import { Link } from 'react-router-dom';

export class LoginPage extends React.Component {
  constructor(props) {
    super(props);
    this.handleLogin = this.handleLogin.bind(this);
  }

  handleLogin(e) {
    e.preventDefault();
    let email = document.getElementById('userEmail').value;
    let password = document.getElementById('userPassword').value;
    this.props.loginHandler(email, password);
  }

  render() {
    return (
      <form onSubmit={ this.handleLogin }>
        <input type="submit" value={ this.props.requestingLogin } />
      </form>
    );
  }
}

export default LoginPage;

登录页面容器.js

import React from 'react';
import { connect } from 'react-redux';
import LoginPage from '../../components/login/LoginPage';
import { loginUser } from '../../actions';

export class LoginPageContainer extends React.Component {
    constructor(props) {
        super(props);
    }

    render() {
        return (
            <LoginPage requestingLogin={ this.props.requestingLogin } loginHandler={ this.props.loginUser } />
        );
    }
}

const mapStateToProps = state => {
    const { loginUserReducer } = state;
    return {
        requestingLogin: loginUserReducer.isRequestingLogin,
    };
};

const mapDispatchToProps = dispatch => {
    return {
        loginUser: (email, password) => { 
            dispatch(loginUser(email, password));
        }
    }
};


export default connect(mapStateToProps,  mapDispatchToProps)(LoginPageContainer);

动作中的 index.js/

export const REQUEST_LOGIN = 'REQUEST_LOGIN';
function requestLogin() {
  return {
    type: REQUEST_LOGIN,
  };
};

export const loginUser = (email, password) => {
    return dispatch => {
        // this works because when the button is clicked,
        // I can successfully console log in here.
        dispatch(requestLogin); // THIS DISPATCH IS NOT WORKING
        // API call here...
    }
};

减速器中的 index.js/

import { combineReducers } from 'redux';
import { REQUEST_LOGIN } from '../actions';

const initialLoginState = {
    isRequestingLogin: false,
};

function loginUserReducer(state = initialLoginState, action) {
    switch(action.type) {
        case REQUEST_LOGIN:
            return Object.assign({}, state, { isRequestingLogin: true });
        default:
            console.log('returned from default');
            return state;
    }
}

const allReducers = combineReducers({
    loginUserReducer,
});

export default allReducers;

奇怪的是，我在dispatch()内部loginUser()工作后的 API 调用有效，但dispatch()无效。

我在网上看过很多教程，我的代码与我所看到的相匹配，但由于某种原因，我无法弄清楚为什么 dispatch action 不起作用。任何帮助将不胜感激。

1个回答

问题在这里：

const mapDispatchToProps = dispatch => {
    return {
        loginUser: (email, password) => { 
            dispatch(loginUser(email, password)); [DISPATCH ACTION]
        }
    }
};

所以 loginUser 是一个函数，它接收电子邮件、密码和调用 dispatch(loginUser(email, password))

但是 loginUser(email, password) 不返回操作，而是返回一个函数。

export const loginUser = (email, password) => {
     return dispatch => {
         // this works because when the button is clicked,
         // I can successfully console log in here.
         dispatch(requestLogin); // THIS DISPATCH IS NOT WORKING
         // API call here...
      }
};

所以该行[DISPATCH ACTION]不会调度动作，而是调度函数。

要使其正确，您可以更改如下：

const mapDispatchToProps = dispatch => {
    return {
        loginUser: (email, password) => {
             loginUser(email, password)(dispatch);
        }
    }
};

所以， loginUser 返回一个函数，你用 dispatch 作为参数调用它。但是好像不好看。如何正确地做到这一点？

export const loginUser = dispatch => {
    return (email, password) => {
        // this works because when the button is clicked,
        // I can successfully console log in here.
        dispatch(requestLogin()); // THIS DISPATCH IS NOT WORKING
        // API call here...
    }
};

在 mapDispatchToProps 中：

const mapDispatchToProps = dispatch => {
    return {
        loginUser: loginUser(dispatch)
    }
};
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