Node.js 12 blocking the event loop

processData.js

function log(...args) {
  console.log(Date.now().toString(), ...args);
}

function processData() {
  log('processing ...');

  for (let i = 0; i < 1000000; i += 1) {
    JSON.parse('{"hello": "world"}');
  }

  return Promise.resolve();
}

async function main() {
  setTimeout(() => log('first timeout: done!'));

  setTimeout(() => {
    processData()
      .then(processData)
      .then(processData)
      .then(processData);
  });

  setTimeout(() => log('second timeout: done!'));
}

main()
  .catch((err) => log(err.message));