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react redux way of printing props

i am trying to include my common component in my main.js
this one I did it it successfully.
but in my common component, I am trying to print my redux data values.
so I created a method called handleClickForRedux to print the values.
I have included mapStateToProps and mapDispatchToProps
but still value is not printing at this line. console.log("event reddux props--->", props);
can you tell me how to fix it.
providing my code snippet and sandbox below.
https://codesandbox.io/s/react-redux-example-265sd
scroll.js
import React, { useEffect, useState, Fragment } from "react";
import PropTypes from "prop-types";
import { withStyles } from "#material-ui/core/styles";
import Card from "#material-ui/core/Card";
//import CardActions from "#material-ui/core/CardActions";
import CardContent from "#material-ui/core/CardContent";
import Typography from "#material-ui/core/Typography";
import Drawer from "#material-ui/core/Drawer";
import { bindActionCreators } from "redux";
import * as actionCreators from "../actions/actionCreators";
import { connect } from "react-redux";
import { compose } from "redux";
function SportsMouse(classes, props) {
// const [canEdit, setCanEdit] = useState(false);
function handleClickForRedux(event) {
console.log("event--->", event);
console.log("event reddux props--->", props);
}
return (
<Card>
<div onClick={handleClickForRedux}>I am here </div>
</Card>
);
}
SportsMouse.propTypes = {
classes: PropTypes.object.isRequired
};
function mapStateToProps(state) {
return {
posts: state.posts,
comments: state.comments
};
}
function mapDispatchToProps(dispatch) {
return bindActionCreators(actionCreators, dispatch);
}
export default compose(
connect(
mapStateToProps,
mapDispatchToProps
)
)(SportsMouse);
main.js
import React from "react";
import { Link } from "react-router-dom";
import Scroll from "../commonComponents/scroll";
const Main = props => {
const { children, match, ...rest } = props;
return (
<div>
<h1>
<Scroll />
<Link to="/">Reduxstagram</Link>
</h1>
{React.Children.map(children, child => React.cloneElement(child, rest))}
</div>
);
};
export default Main;

Even when using material-ui, components only accept one argument. classes exists inside props. If you console.log(classes) you'll see that it contains all of your props, including material-ui's styles. It should be this:
function SportsMouse(props) {

React-redux connect() fails to pass the props

I'm trying to learn react-redux architecture, and I failed on the most basic stuff.
I created class HomePage and used react-redux connect() to connect it to store's state and dispatch.
import React, { Component } from 'react';
import PropTypes from 'prop-types';
import {HomeButtonClickAction} from "./HomeActionReducer";
import {connect} from "react-redux";
class HomePage extends Component {
constructor(props) {
super(props);
console.log('HomePage props');
console.log(this.props);
this.buttonClicked = this.buttonClicked.bind(this);
}
buttonClicked() {
console.log('button cliked');
this.props.buttonClick();
}
render() {
console.log('Re-rendering...');
let toggleState = this.props.toggle ? 'ON' : 'OFF';
return (
<div>
<button onClick={this.buttonClicked}>{ toggleState }</button>
</div>
)
}
}
HomePage.propTypes = {
toggle: PropTypes.bool.isRequired,
onClick: PropTypes.func.isRequired
};
const mapStateToProps = (state, ownProps) => {
return {
toggle: state.toggle
}
};
const mapDispatchToProps = (dispatch, ownProps) => {
return {
buttonClick: () => {
dispatch(HomeButtonClickAction());
}
}
};
const HomeContainer = connect(
mapStateToProps,
mapDispatchToProps
)(HomePage);
export default HomePage;
But it's not working for me. HomeContainer doesn't pass props to HomePage component.
I've got these warnings in devtools.
My index.js looks like this.
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import registerServiceWorker from './registerServiceWorker';
import AppReducer from "./reducers/AppReducer";
import { createStore } from "redux";
import { Provider } from 'react-redux';
const store = createStore(AppReducer);
ReactDOM.render(
<Provider store={ store }>
<App/>
</Provider>,
document.getElementById('root')
);
registerServiceWorker();
and AppReducer.js
import { combineReducers } from 'redux';
import { toggle } from '../home/HomeActionReducer';
const AppReducer = combineReducers({
toggle
});
export default AppReducer;
and HomeActionReducer.js
const HOME_BUTTON_CLICK = 'HOME_BUTTON_CLICK';
export function toggle (state = true, action) {
console.log('toggle launched');
switch (action.type) {
case HOME_BUTTON_CLICK :
return !state;
default:
console.log('Toggle reducer default action');
return state;
}
}
export function HomeButtonClickAction() {
console.log('action emitted');
return {
type: HOME_BUTTON_CLICK
};
}
Being a newbie I'll really appreciate your help :)

You are exporting HomePage, which is the presentational component. You want to export HomeContainer, which is the container that passes the props to HomePage through connect.
So replace this
export default HomePage;
with this
export default HomeContainer;
You can also directly write
export default connect(mapStateToProps, mapDispatchToProps)(HomePage);
Note that, since it's the default export, you can name the import as you want, eg.:
import HomePage from './HomePage' // even if it's HomeContainer that is exported

You have this:
const HomeContainer = connect(
mapStateToProps,
mapDispatchToProps
)(HomePage);
export default HomePage;
To create an instance of the connect component you need to do this:
export default connect()(HomePage);
Notice I did not write export default twice, bad practice, you only export default once per component so the connect() goes inside that same line of code and the invocation or second set of parentheses you wrap around the component you are working in.
This connect() function is actually a React component that you are going to pass some configuration to and the way you begin to do that is by calling mapStateToProps like so:
const mapStateToProps = () => {
};
export default connect()(HomePage);
You could also do:
function mapStateToProps() {
}
If you read it, it makes sense, this is saying that we are going to map our state object, all the data inside the redux store and run some computation that will cause that data to show up as props inside our component, so thats the meaning of mapStateToProps.
Technically, we can call it anything we want, it does not have to be mapStateToProps, but by convention we usually call it mapStateToProps and its going to be called with all the state inside of the redux store.
const mapStateToProps = (state) => {
};
export default connect()(HomePage);
The state object contains whatever data you are trying to access from the redux store. You can verify this by console logging state inside the function like so:
const mapStateToProps = (state) => {
console.log(state);
return state;
};
export default connect()(HomePage);
I am returning state just to ensure that everything is working just fine.
After defining that function, you take it and pass it as the first argument to the connect() component like so:
const mapStateToProps = (state) => {
console.log(state);
return state;
};
export default connect(mapStateToProps)(HomePage);
Thats how we configure the connect component.We configure it by passing it a function. Run that and see what happens.

Print value from props, which is delivered to the component from redux by mapStateToProps

Problem:
I can't display the value from the state of redux, which is delivered by mapStateToProps function to the component.
Project structure:
Create-react-app CLi application built the project.
Inside of the src/ I have the following code structure
Necessary code:
The main page which we are interacting with looks like this:
Underneath it is planned to post the result of the clicking on the buttons.
So how do I bind the redux state and actions to those two components: Calculator and ResultLine?
Let me show the index.js code, where I create the store:
import React from "react";
import ReactDOM from "react-dom";
import { Provider } from "react-redux";
import { createStore } from "redux";
import reducers from './reducers/';
import App from './components/App';
ReactDOM.render(
<Provider store={createStore(reducers)}>
<App />
</Provider>,
document.getElementById("root")
);
There are only three actions:
import {CALCULATE, ERASE, PUT_SYMBOL} from "./types";
export const putSymbol = (symbol) => {
return {
type: PUT_SYMBOL,
payload: symbol
}
};
export const calculate = () => {
return {
type: CALCULATE
}
};
export const erase = () => {
return {
type: ERASE
}
};
And in the App.js I pass reducers, which are binded to those actions to the Calculator component:
import React, {Component} from 'react';
import Calculator from './Calculator';
import ResultLine from "./ResultLine";
import {calculate, erase, putSymbol} from "../actions/index";
import {connect} from "react-redux";
class App extends Component {
render() {
return (
<div>
<Calculator
onSymbolClick={this.props.onSymbolClick}
onEqualsClick={this.props.onEqualsClick}
onEraseClick={this.props.onEraseClick}/>
<br/>
<ResultLine result={this.props.result}/>
</div>
);
}
}
const mapStateToProps = (state) => {
console.log('mapState', state.calc.line);
return {
result: state.line
}
};
const mapDispatchToProps = {
onSymbolClick: putSymbol,
onEqualsClick: calculate,
onEraseClick: erase
};
export default connect(mapStateToProps, mapDispatchToProps)(App);
And that works fine. Whenever I click the button the state changes, and I observe it in the console log, called in mapStateToProps function.
So I expect, that I can deliver result prop to the Result line easily, and I pass it into the ResultLine component as a parameter. So, let's look at that element:
import React from 'react';
const ResultLine = ({result}) => {
return (
<p>{result}</p>
);
};
export default ResultLine;
And I can see no changes in a result line. Maybe, something wrong with the React/Redux lifecycle management and ResultLine component just does not update on changes in state?

There's an error on mapStateToProps.
Instead of:
const mapStateToProps = (state) => {
return {
result: state.line
}
}
Please use:
const mapStateToProps = (state) => {
return {
result: state.calc.line // calc was missing here
}
}

React/Redux - Why is my action/reducer not working?

Newbie here. Trying to get my Redux action to talk to my reducer and update the store. - TL;DR question further down:
Context: I am only really getting issues now that i'm trying to split out my actions/reducers into separate files and folders. Prior to this i got everything working, when it was all in one file, sort of thing.
So... I have 3 files.
i) A Client.js (top level, where my store is), which takes my reducer in and then uses provider to get the store to <Main />
Main.js then uses mapDispatchToProps to get a toggleLogin action(creator) into its onClick prop.
This is then passed down to <LoginButton /> where onClick can be clicked. And when it is, i can get a console log from the toggleLogin action-creator. But any attempt to return { type: 'TOGGLE_LOGIN' } sees either a:
'ReferenceError: store is not defined' or no change... and i have to console.log either side to find the problem sits within that return {} area. So...
TL;DR Question why wont my reducer pick-up that action and update the store? Its driving me nutty.
ClientJS:
import React from 'react';
import ReactDOM from 'react-dom';
import Redux from 'redux';
import Main from './Components/Main'
import { myReducer } from './Reducers/reducer';
import { createStore } from 'redux';
import { Provider } from 'react-redux';
const store = createStore(myReducer);
ReactDOM.render(
<Provider store={store}>
<Main />
</Provider>,
document.getElementById('root')
);
Main.Js
import React from 'react';
import LoginButton from './LoginButton';
import PlayButton from './PlayButton';
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux';
import { toggleLogin } from '../actions/toggleLogin';
const Main = (props) => {
const { onClick} = props;
return (
<div>
<h1>hello world</h1>
<LoginButton onClick={onClick} />
<PlayButton />
</div>
);
};
const mapStateToProps = (state) => {
return {
isLoggedIn: state.isLoggedIn
}
}
const mapDispatchToProps = (dispatch) => {
return bindActionCreators({
onClick: toggleLogin,
}, dispatch)
}
export default connect(mapStateToProps, mapDispatchToProps)(Main);
reducer.js:
export const myReducer = (state = { isLoggedIn: false }, action) => {
switch (action.type) {
case 'TOGGLE_LOGIN':
return {
isLoggedIn: !action.isLoggedIn
}
default:
return state;
}
};
LoginButton.js
import React from 'react';
import Redux from 'redux';
const LoginButton = (props) => {
const { onClick } = props;
return (
<div>
<button onClick={onClick}>LOGIN/LOGOUT</button>
</div>
);
};
export default LoginButton;
toggleLogin.js (action creator):
export function toggleLogin() {
console.log('this works');
store.dispatch({
type: 'TOGGLE_LOGIN',
});
console.log('this doesnt work');
}

toggleLogin should just return {type: 'TOGGLE_LOGIN'}. bindActionCreators is what wraps that function in a store.dispatch call, so you are basically trying to dispatch what another dispatch returns.
Also you get that 'ReferenceError: store is not defined' exception because inside your function there is no store reference.

Just closing the loop on this one - looks like it was a mesh of things:
i) my TOGGLE_LOGIN was indeed trying to dispatch. It should've just been returning an object.
ii) i did need bindActionCreators but it would've been more appropriate with more than one action.
iii) most importantly - when i was changing my TOGGLE_LOGIN to return an object... i was putting two console logs either side of it, for debugging purposes. But being a newbie/absent minded, i totally overlooked that this was effectively putting a function after a return statement. Once i took the console-logs off, i was up and running. Thanks everyone.

React + Redux: Component does not update

Trying out React + Redux, and probably am doing something obviously stupid, because a component that fires an action to fetch data over the network does not get updated (re-rendered) when the data is fetched.
Here are the relevant bits of my code:
The top-level index.js serving as an entry point for the app:
import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import { createStore, applyMiddleware } from 'redux';
import { Router, browserHistory } from 'react-router';
import reduxPromise from 'redux-promise';
import createLogger from 'redux-logger';
const logger = createLogger();
import routes from './routes';
import reducers from './reducers';
const createStoreWithMiddleware = applyMiddleware(reduxPromise, logger)(createStore);
ReactDOM.render(
<Provider store={createStoreWithMiddleware(reducers)}>
<Router history={browserHistory} routes={routes} />
</Provider>
, document.querySelector('.container'));
Top-level container App:
import React, {Component} from 'react';
import { bindActionCreators } from 'redux';
import { connect } from 'react-redux';
import * as Actions from '../actions';
import Header from '../components/header';
import Showcase from '../components/showcase';
function mapStateToProps(state) {
return {
resources: state.resources
}
}
function mapDispatchToProps(dispatch) {
return {
fetchResources: () => {
dispatch(Actions.fetchResources());
}
}
}
class App extends Component {
render() {
console.log('props in App', this.props);
return (
<div>
<Header/>
<Showcase
fetchResources={this.props.fetchResources}
resources={this.props.resources}
/>
</div>
);
}
}
export default connect(
mapStateToProps,
mapDispatchToProps
)(App)
Component that triggers an action to sends a request for data when it is about to mount and is supposed to show the fetched data:
import React, {Component} from 'react';
import {connect} from 'react-redux';
class Showcase extends Component {
constructor(props) {
super(props);
}
componentWillMount() {
this.props.fetchResources();
}
render() {
console.log('resources', this.props);
return (
<div>
This is showcase
</div>
);
}
}
export default connect(state => ({resources: state.resources}))(Showcase)
Action Creator:
import * as types from '../constants/ActionTypes';
import axios from 'axios';
export function fetchResources() {
return {
type: types.FETCH_FIRST,
payload: axios.get('/sampledata/1.json')
}
}
Reducer for the fetch action:
import * as types from '../constants/ActionTypes';
export default function resourcesReducer (state={}, action) {
switch (action.type) {
case types.FETCH_FIRST:
console.log('about to return', Object.assign (state, {resources: action.payload.data }))
return Object.assign (state, {resources: action.payload.data });
default:
return state
}
};
and finally the root reducer:
import { combineReducers } from 'redux';
import navigationReducer from './navigation-reducer';
import resourcesReducer from './resources-reducer';
const rootReducer = combineReducers({
navigationReducer,
resourcesReducer
});
export default rootReducer;
So, here is what I am observing. The action to request data is successfully triggered, a request is sent, the reducer receives it when the promise is resolved, and updates the state with the fetched data. At this point, I would expect the top-level App component and the Showcase component to detect that the store has updated, and to re-render, but I do not see it in the console.
Also, I am confused by redux-logger’s console output:
Specifically, I am surprized to see that the state contains reducers from the rootReducer — I don't know if it's right (an example on Redux logger Github page shows a state without reducers). It also seems surprising that the prev state as reported by redux-logger contains the same resourcesReducer object as the next state, although intuitively I would expect prev state to be more or less empty.
Could you please point out what I am doing wrong and how to get React components respond to the state changes?
==================================================
UPDATED:
1) Changed the mapStateToProps function in the App component so that it correctly maps to reducer states:
function mapStateToProps(state) {
return {
resources: state.resourcesReducer
}
}
2) Still passing the resources down to the `Showcase component:
render() {
console.log('props in App', this.props);
return (
<div>
<Header navigateActions={this.props.navigateActions}/>
React simple starter
<Showcase
fetchResources={this.props.fetchResources}
resources={this.props.resources}
/>
</div>
);
3) Trying to display resources on the screen by stringifying it to see what’s actually inside this object:
render() {
console.log('resources', this.props);
return (
<div>
This is showcase {JSON.stringify(this.props.resources)}
</div>
);
}
See this on the screen: This is showcase {}. The component does not seem to re-render.
Here’s the screenshot of the console showing that App’s props have updated with the values from the next state. Still, that did not cause the component to re-render:
UPDATED AGAIN: And my javascript-fu was poor, too. I did not quite realize that by returning Object.assign (state, {resources: action.payload.data }); I was in fact mutating the state, and that a simple inversion of arguments would let me achieve what I intended. Thanks to this discussion on SO for enlightenment.

I am surprized to see that the state contains reducers from the rootReducer
This is how it works. Take a closer look at combineReducers().
const rootReducer = combineReducers({
navigationReducer,
resourcesReducer
});
Recognise that it's not a list of parameters; it's a single object parameter. Perhaps it is clearer in verbose syntax:
var rootReducer = combineReducers({
navigationReducer: navigationReducer,
resourcesReducer: resourcesReducer
});
The resourcesReducer key points to the state returned by the resourcesReducer() function. That is, the state variable within the resourcesReducer() is just one part of the entire state.
The functions passed to connect() take the entire state as an argument. What yours should actually look like is this:
export default connect(state => ({
resources: state.resourcesReducer.resources
}))(Showcase);