How to dispatch an action on load?

You can dispatch an action in componentDidMount() method and in render() method you can verify the data.

class App extends Component {
componentDidMount() {
this.props.fetchData();
}

render() {
return this.props.isLoaded ? (
) : (
);
}
}

const mapStateToProps = (state) => ({
isLoaded: state.isLoaded,
});

const mapDispatchToProps = { fetchData };

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