Very new to react and redux and cannot work out why I cannot access the state via this.props within a functional component.
Store
I create the initial state for rotating and pass this into my store upon creation.
import { createStore } from "redux";
import rotateReducer from "../reducers/rotateReducer";
const initialState = { rotating: true }
const store = createStore(rotateReducer, initialState)
export default store;
Reducer
Function to change state of rotating.
export default (state,action) => {
if (action.type === "rotate") {
return { rotating: action.payload }
}
return state;
}
Index.js
Here I import the store and Provider and wrap the App component passing in store as a prop.
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';
import { Provider } from "react-redux";
import store from "./store/store";
ReactDOM.render(
<Provider store={store}>
<App />
</Provider>,
document.getElementById('root')
);
App.js
Main component where I am trying to load the props, but keeping getting "cannot read property 'props' of undefined"
import React from 'react';
import logo from './logo.svg';
import './App.css';
import { connect } from "react-redux";
import { startAction } from "./actions/startAction";
import { stopAction } from "./actions/stopAction";
function App() {
return (
<div className="App">
<header className="App-header">
<img
src={logo}
className={
"App-logo" +
(this.props.rotating ? "":" App-logo-paused")
}
alt="logo"
onClick={
this.props.rotating ?
this.props.stopAction : this.props.startAction
}
/>
<p>
Edit <code>src/App.js</code> and save to reload.
</p>
<a
className="App-link"
href="https://reactjs.org"
target="_blank"
rel="noopener noreferrer"
>
Learn React
</a>
</header>
</div>
);
}
const mapStateToProps = state => ({
...state
});
const mapDispatchToProps = dispatch => {
return {
startAction: () => dispatch(startAction),
stopAction: () => dispatch(stopAction)
}
}
export default connect(mapStateToProps, mapDispatchToProps)(App);
You should put props as a paramter:
function App(props) {
console.log(props)
return(/* .... */)
}
Try this and check the console output. (this.props would work in a class component, but I prefer to use function components)
I usually only add the parts of the state that I need:
function mapStateToProps(state) {
return {
rotating: state.rotating
}
}
And then:
function App({rotating, /* more variables */}) {
console.log(rotating)
return(/* .... */)
}
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