SignalR listener not getting invoked in React Native - react-native

Question

I am building a mobile app in React Native for a backend written in .NET. The backend has implemented a realtime messaging service using SignalR Hubs. I am using the package react-native-signalr. The connection is getting established, and I can send message to SignalR hub by calling proxy.invoke. The problem is in reception of message. I tried with proxy.on but nothing happens.
componentDidMount(){
const { access_token } = this.props;
// Setup connection to signalr hub.
const hubUrl = `${API_URL}/signalr`;
const connection = signalr.hubConnection(hubUrl);
const proxy = connection.createHubProxy('MessagesHub', {queryParams: { token: access_token }});
// Start connection
connection.start();
// Trying to receive message from SignalR Hub
proxy.on('messageReceived', message => {
console.log(message);
})
proxy.on('sendPrivateMessage', message => {
console.log(message);
})
proxy.on('sentPrivateMessage', message => {
console.log(message);
})
}

Answer 1

when you register a listener with your_proxy.on function ,you must define a function with required parameters and bind it on constructor and then pass it to your_proxy.on function ,see bellow:
constructor(props){
super(props);
this.messageReceived=this.messageReceived.bind(this); // <========== **Important**
this.sendPrivateMessage=this.sendPrivateMessage.bind(this); // <========== **Important**
this.sentPrivateMessage=this.sentPrivateMessage.bind(this); // <========== **Important**
}
messageReceived(message ){
console.log(message);
}
sendPrivateMessage(message ){
console.log(message);
}
sentPrivateMessage(message ){
console.log(message);
}
componentDidMount(){
const { access_token } = this.props;
// Setup connection to signalr hub.
const hubUrl = `${API_URL}/signalr`;
const connection = signalr.hubConnection(hubUrl);
const proxy = connection.createHubProxy('MessagesHub', {queryParams: { token: access_token }});
// Trying to receive message from SignalR Hub
proxy.on('messageReceived', this.messageReceived);
proxy.on('sendPrivateMessage', this.sendPrivateMessage);
proxy.on('sentPrivateMessage', this.sentPrivateMessage);
// Start connection
connection.start();
}