main.js

const { Query, queryProviders, sleep } = require('eth-sdk');
const webSocketConstructor = require('ws');

async function main() {
  const provider = new queryProviders
    .WebSocketProvider('wss://ropsten.infura.io/ws', {
      webSocketConstructor,
    });

  provider.state$.subscribe((state) => {
    console.log('provider.state:', state);
  });

  const query = new Query(provider);

  console.log('query.net.version:', await query.net.version);

  const newHeads$ = await query.subscription.create(
    'newHeads',
  );

  const logs$ = await query.subscription.create(
    'logs',
    {
      address: '0x680BD7850c4F3277D765707B9a53Dc2Da98276f3',
    }
  );

  const newPendingTransactions$ = await query.subscription.create(
    'newPendingTransactions',
  );

  newHeads$
    .subscribe((result) => {
      console.log('query.subscription.newHeads$', result);
    });

  logs$
    .subscribe((result) => {
      console.log('query.subscription.logs$:', result);
    });

  newPendingTransactions$
    .subscribe((result) => {
      console.log('query.subscription.newPendingTransactions$:', result);
    });

  await sleep(30000); // sleep for 30 sec.

  // unsubscribe:
  await newHeads$.unsubscribe();

  // unsubscribe all:
  await query.subscription.unsubscribeAll();

  await provider.disconnect();
}

main()
  .catch(console.log);