rxjs - detailed socket.io

detailedSocketIO.js

import { fromEvent, Subject } from 'rxjs';
import { map, shareReplay, switchMap } from 'rxjs/operators';
import io from 'socket.io-client';

const $token = new Subject();
const $client = $token.pipe(
  map((token) => {
    if (null == token || '' === token) {
      return {};
    }
    return {
      transportOptions: {
        polling: {
          extraHeaders: {
            authorization: 'Bearer ' + token,
          },
        },
      },
    };
  }),
  map((config) => io('/', config).connect()),
  shareReplay(1),
);
const listen = (event) =>
  $client.pipe(
    switchMap((client) => fromEvent(client, event)),
    shareReplay(1),
  );

listen('message').subscribe((message) =>
  console.log(message.author + ': ' + message.content),
);