Can't connect to server because of CORS (Reason: CORS header ‘Access-Control-Allow-Origin’ missing)

This is my app.module.ts:

import { SocketIoModule, SocketIoConfig } from 'ngx-socket-io';

const config: SocketIoConfig = { url: 'http://localhost:4000', options: {} };

@NgModule({
  declarations: [AppComponent, MapComponent],
  imports: [BrowserModule, HttpClientModule, SocketIoModule.forRoot(config)],
  providers: [],
  bootstrap: [AppComponent],
})
export class AppModule {}

this is my server:

const server = require('http').createServer();
const options = {
  origin: '*',
  methods: ['GET', 'POST'],
};

server.listen(4000, () => {
  console.log('Server ready....');
});

const io = require('socket.io')(server, options);

io.on('connection', (socket) => {
  console.log('Connected');
  socket.emit('data', JSON.stringify(data));

});

This is how I am trying to get data from socket server in my service:

  getMarkers(): Observable<IMarker[]> {
    return this.socket.fromEvent<string>('data').pipe(map((data: string) => JSON.parse(data)));
  }

Every time I open localhost:4200 I get CORS error:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:4000/socket.io/?EIO=3&transport=polling&t=NReqqZ8. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).

Don’t know what to set here to make CORS works:

const options = {
  origin: '*',
  methods: ['GET', 'POST'],
};

[k-matti]

I fixed CORS issue by adding this to config in my app:

SocketIoModule.forRoot({
      url: 'http://localhost:4000',
      options: {
        withCredentials: false,
      },
    }),

server:

const server = require('http').createServer();
const options = {
  cors: {
    origin: '*',
  },
};

const io = require('socket.io')(server, options);

io.on('connection', (socket) => {
  console.log('Connected');
});

server.listen(4000);

But still on app start i am not connected to socket, can’t see connected in the console

[Helveg]

Any errors? You’d have to show us the code you use to connect to the server, but a better place for troubleshooting is on other community channels like StackOverflow.