wire service for off-core LWC that subscribes to a websocket

implementation.js

import wsSubscribe from '../../messages/wsWire/wsWire';

@wire(wsSubscribe, { uri: location.href.replace(/^http/, 'ws'), log: true, fake: true })
  wiredResults({ error, data }) {
    if (error) {
      console.error('error from ws subscribe wire', error);
    } else if (data) {
      console.log(data);
      this.results = data;
    }
  }

wsWire.js

/* eslint-disable @lwc/lwc/no-async-operation */
import { register, ValueChangedEvent } from '@lwc/wire-service';
// if you want to set your wire to mock data for building complex ui without connecting to real data
import * as fakeData from '../../route/deployMessages/__tests__/data/fullExample.json';

export default function wsSubscribe() {
  // eslint-disable-next-line no-unused-vars
  return new Promise((resolve, reject) => {
    resolve();
  });
}

register(wsSubscribe, eventTarget => {
  let config;
  let pinger;
  let ws;

  eventTarget.addEventListener('config', newConfig => {
    if (newConfig.log) {
      console.log('new config is', newConfig);
    }
    config = newConfig;
  });

  eventTarget.addEventListener('connect', () => {
    if (config.fake) {
      eventTarget.dispatchEvent(new ValueChangedEvent({ data: fakeData.default }));
    } else {
      if (config.log) {
        console.log('ws is connecting');
      }

      ws = new WebSocket(config.uri);
      ws.onopen = () => {
        if (config.log) {
          console.log('WS is open!');
        }
        pinger = setInterval(() => {
          try {
            ws.send('ping');
          } catch (e) {
            console.log('could not send ws ping', e);
          }
        }, 5000);
      };

      ws.onmessage = event => {
        const newData = JSON.parse(event.data);
        if (config.log) {
          console.log('heard ws event', newData);
        }
        eventTarget.dispatchEvent(new ValueChangedEvent({ data: newData }));
      };

      ws.onclose = () => {
        if (config.log) {
          console.log('WS is closing');
        }
        clearInterval(pinger);
      };
    }
  });

  eventTarget.addEventListener('disconnect', () => {
    ws.close();
    clearInterval(pinger);
  });
});