ASP.NET Core SignalR chat with React.js - https://codingblast.com/asp-net-core-signalr-chat-react

Chat.jsx

componentDidMount = () => {
  const nick = window.prompt('Your name:', 'John');

  const hubConnection = new HubConnection('http://localhost:5000/chat');

  this.setState({ hubConnection, nick }, () => {
    this.state.hubConnection
      .start()
      .then(() => console.log('Connection started!'))
      .catch(err => console.log('Error while establishing connection :('));
  });
}