https://x.com/minsangk/status/1808327029240291465 (snapped from https://github.com/wickedev/fp-benchmark)

twitter-nerds-iterate.js

console.clear();

async function bootstrap() {
  const N = 100_000_000;
  console.log(`N: ${N}`);

  console.time("init numbers");

  const rangeLen = (b) => Array.from({ length: b }).map((_, i) => i)
  const numbers = rangeLen(N).map(() => Math.floor(Math.random() * 10));
  const square = (x) => x * x;
  const isEven = (x) => x % 2 === 0;
  const add = (acc, x) => acc + x;
  console.timeEnd("init numbers");;

  console.log("");

  await (async () => {
    const start = performance.now()

    let sumOfSquares = 0;
    for (let i = 0; i < numbers.length; i++) {
      if (numbers[i] % 2 === 0) {
        sumOfSquares += numbers[i] * numbers[i];
      }
    }

    console.log(`for: ${performance.now() - start}`);
    console.log(sumOfSquares)
  })();

  console.log("");

  await (async () => {
    const start = performance.now()

    let sumOfSquares = 0;
    for (let number of numbers) {
      if (number % 2 === 0) {
        sumOfSquares += number * number;
      }
    }

    console.log(`for-of: ${performance.now() - start}`);
    console.log(sumOfSquares)
  })();

  console.log("");

  await (async () => {
    const start = performance.now()
    const sumOfSquares = numbers
      .filter(isEven)
      .map(square)
      .reduce(add, 0);

    console.log(`raw-map-filter-reduce: ${performance.now() - start}`);
    console.log(sumOfSquares)
  })();

  console.log("");

  await (async () => {
    const start = performance.now()
    const sumOfSquares = numbers.reduce((a, b) => isEven(b) ? add(a, square(b)) : a, 0)

    console.log(`reduce: ${performance.now() - start}`);
    console.log(sumOfSquares)
  })();

  console.log("");
}

bootstrap().finally(async () => { });