[Ethereum] web3 Websocket connection to infura

I don't want to get a "golden shovel" reward or something but that question doesn't seem to be very old. I managed to successfully implement automatic reconnect thus I wanted to share the code:

First I created a separate function getProvider:

function getProvider() {
  const { WebsocketProvider } = Web3.providers;

  const provider = new WebsocketProvider(WEB3_WEBSOCKET_PROVIDER_URL);

  return new Promise((resolve) => {
    provider.on('connect', () => {
      logger.info('Web3 WS connected.');
      return resolve(provider);
    });

    provider.on('error', () => resolve());
  });
}

Then I have a function listen that attaches to blockchain in order to listen for events that I'm interested in:

async function listen(repositories, wallet) {
  const provider = await getProvider();

  if (!provider) {
    logger.info('Web3 WS unavailable. Reconnecting...');
    setTimeout(() => listen(repositories, wallet), 5000);
    return;
  }

  const web3 = new Web3(provider);

  provider.on('error', (e) => {
    logger.error(`Web3 WS encountered an error: ${e}.`);
    listen(repositories, wallet);
  });

  provider.on('end', () => {
    logger.error('Web3 WS disconnected. Reconnecting...');
    listen(repositories, wallet);
  });

  const contractsConnector = contractsConnectorFactory(web3);
  const contracts = await contractsConnector.connectAll();

  const listeners = listenersFactory(repositories, contracts, wallet);
  listeners.attachAll();
}

This way whenever the connection closes I make sure that I won't miss any events that were thrown in the meantime. Hope that helps anyone that will have problems with that.

I think I've worked out what the problem is.

Since my "client" doesn't technically need a webserver, I ran my html app directly from my desktop, i.e. it was executing from this url in chrome:

file:///C:/Users/Latheesan/Desktop/Crypto%20Election/index.html

After I moved it into a local webserver (e.g. apache) and running it from this url:

http://localhost/Crypto%20Election/

It's now working, I am no longer getting CORS errors.