fibonacci.js

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

function fib1(n) {
  let s = [0, 1, 1];

  for (let i = 3; i <= n; i++) {
    s.push(s[s.length - 1] + s[s.length - 2])
  }

  return s[s.length - 1]
}

function fib2(n) {
  let a = 1;
  let b = 1;
  for (let i = 3; i <= n; i++) {
    let c = a + b;
    a = b;
    b = c;
  }
  return b;
}

let start = performance.now();
fib1(5)
fib1(13)
fib1(77)
console.log('fib1\t', performance.now() - start);

start = performance.now();
fib2(5)
fib2(13)
fib2(77)
console.log('fib2\t', performance.now() - start);