Array.include vs Set.has

compare-performance.js

const arr = Array.from({ length: 10000 }, (_, i) => i);
const set = new Set(arr);

function checkArr() {
  return arr.filter((item) => arr.includes(item));
}

function checkSet() {
  return arr.filter((item) => set.has(item));
}

function checkPerformance(callback) {
  const start = performance.now();
  callback();
  const end = performance.now();

  return end - start;
}

const arrResults = [];
const setResults = [];

for (let i = 0; i < 100; i++) {
  arrResults.push(checkPerformance(checkArr));
  setResults.push(checkPerformance(checkSet));
}

function calcAverage(result) {
  return result.reduce((acc, next) => acc + next, 0)/result.length;
}

console.log('arr:', calcAverage(arrResults));
console.log('set:', calcAverage(setResults));

length: 10k

arr: 31.427812070995568
set: 0.2702250306308269

length: 1k

arr: 0.41436250001192093
set: 0.038988359719514844

length: 100

arr: 0.009791249185800552
set: 0.007861280143260955