silphius/app/client/prediction.js

import {encode} from '@/net/packets/index.js';
import {withResolvers} from '@/util/promise.js';

let connected = false;
let socket;

function onMessage(event) {
  postMessage(event.data);
}

onmessage = async (event) => {
  if (!connected) {
    const url = new URL(`wss://${event.data.host}/ws`)
    socket = new WebSocket(url.href);
    socket.binaryType = 'arraybuffer';
    const {promise, resolve} = withResolvers();
    socket.addEventListener('open', resolve);
    socket.addEventListener('error', () => {
      postMessage(encode({type: 'ConnectionStatus', payload: 'aborted'}));
      close();
    });
    await promise;
    socket.removeEventListener('open', resolve);
    socket.addEventListener('message', onMessage);
    socket.addEventListener('close', () => {
      postMessage(encode({type: 'ConnectionStatus', payload: 'aborted'}));
      close();
    });
    postMessage(encode({type: 'ConnectionStatus', payload: 'connected'}));
    connected = true;
    return;
  }
  socket.send(event.data);
};