threads.js

process.env.UV_THREADPOOL_SIZE = 5;

const crypto = require('crypto');

const start = Date.now();
crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
  console.log('1:', Date.now() - start);
});

crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
  console.log('2:', Date.now() - start);
});

// Lets detect the presence of the 4 Threads pool from libuv

crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
  console.log('3:', Date.now() - start);
});

crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
  console.log('4:', Date.now() - start);
});

// This last entry will need to wait for the 4 calls to complete
// Because it is taking the 4 available threads inside libuv Thread pool
crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
  console.log('5:', Date.now() - start);
});