bench-node.js

const { performance } = require('perf_hooks');

const fibo = fib()

function fib() {
  let x = 0
  let y = 1
  return function () {    
    const temp = x;
    x = x + y;
    y = temp;
    return y
  }
}
var text = 'For more information, see Chapter 3.4.5.1'
var t0 = performance.now();
for (let j=0; j<100; j++) {
for (let i=0; i<100; i++){
    str = new Date()
    d = new Date(str)
    found = text.match(/see (chapter \d+(\.\d)*)/i);
    console.log(fibo(), str.toString(), found, d)        
}
}
var t1 = performance.now();
console.log("Call to doSomething took " + (t1 - t0) + " milliseconds.");

// standart x1 770 ms
// laptop asus 620 ms
// c5.large  570 ms
// m5.large 620 ms