threadsjs.js

const spawn = require('threads').spawn;

const thread = spawn(function(input, done) {
  // Everything we do here will be run in parallel in another execution context.
  // Remember that this function will be executed in the thread's context,
  // so you cannot reference any value of the surrounding code.
  done({ string : input.string, integer : parseInt(input.string) });
});

thread
  .send({ string : '123' })
  // The handlers come here: (none of them is mandatory)
  .on('message', function(response) {
    console.log('123 * 2 = ', response.integer * 2);
    thread.kill();
  })
  .on('error', function(error) {
    console.error('Worker errored:', error);
  })
  .on('exit', function() {
    console.log('Worker has been terminated.');
  });