Generator vs Array vs Inline iteration

README.md

In this test, inline is 10x faster than arrayt which is 1.4x faster than generator.

main.js

#!#!/bin/node --expose-gc

function time(fn) {
  if (global.gc) {
    global.gc();
  }
  const start = process.hrtime.bigint();
  fn();
  const end = process.hrtime.bigint();
  return end - start;
}

function* generator(start, end, interval = 1) {
  while (start < end) {
    yield start;
    start += interval;
  }
}

function array(start, end, interval = 1) {
  const a = new Array(Math.floor(end - start) / interval);
  for (let i = 0; i < a.length; i++) {
    a[i] = start;
    start += interval;
  }
  return a;
}

function iterate(numbers) {
  for (const n of numbers) {
    if (1e9 < n) {
      process.exit(1);
    }
  }
}

function iterateInline(start, end, interval = 1) {
  for (; start < end; start += interval) {
    if (1e9 < start) {
      process.exit(1);
    }
  }
}

for (let i = 20; i < 25; i++) {
  for (let n = 0; n < 2; n++) {
    console.log(
      `generator 2^${i}\t${time(() => iterate(generator(0, Math.pow(2, i)))) /
        1000n /
        1000n} ms`,
    );
    console.log(
      `array 2^${i}\t${time(() => iterate(array(0, Math.pow(2, i)))) /
        1000n /
        1000n} ms`,
    );
    console.log(
      `inline 2^${i}\t${time(() => iterateInline(0, Math.pow(2, i))) /
        1000n /
        1000n} ms`,
    );
  }
  console.log();
}

output.txt

generator 2^20	25 ms
array 2^20	21 ms
inline 2^20	2 ms
generator 2^20	25 ms
array 2^20	20 ms
inline 2^20	2 ms

generator 2^21	47 ms
array 2^21	39 ms
inline 2^21	3 ms
generator 2^21	47 ms
array 2^21	32 ms
inline 2^21	3 ms

generator 2^22	90 ms
array 2^22	67 ms
inline 2^22	6 ms
generator 2^22	90 ms
array 2^22	66 ms
inline 2^22	6 ms

generator 2^23	188 ms
array 2^23	135 ms
inline 2^23	12 ms
generator 2^23	184 ms
array 2^23	132 ms
inline 2^23	13 ms

generator 2^24	367 ms
array 2^24	262 ms
inline 2^24	24 ms
generator 2^24	369 ms
array 2^24	256 ms
inline 2^24	25 ms