When we need to update the state of the parent component from its child, we can create an event handler (updateState) in the parent component and pass it as a prop (updateStateProp) to the child component where we can just call it.
App.jsx
import React from ‘react’;
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
data: ‘Initial data…’
}
this.updateState = this.updateState.bind(this);
};
updateState() {
this.setState({data: ‘Data updated from the child component…’})
}
render() {
return (
<div>
<Content myDataProp = {this.state.data}
updateStateProp = {this.updateState}></Content>
</div>
);
}
}
class Content extends React.Component {
render() {
return (
<div>
<button onClick = {this.props.updateStateProp}>CLICK</button>
<h3>{this.props.myDataProp}</h3>
</div>
);
}
}
export default App;
main.js
import React from ‘react’;
import ReactDOM from ‘react-dom’;
import App from ‘./App.jsx’;
ReactDOM.render(<App/>, document.getElementById(‘app’));