Which JavaScript Loop Is Fastest? Benchmark Results Revealed

Loops are a built‑in feature of any programming language, and JavaScript provides many ways to iterate over data. This article tests several JavaScript looping methods to find out which is the fastest.

For Loop

While Loop

Do‑While Loop

For‑In Loop (excluded from the test)

For‑Of Loop

forEach Loop

Map Loop

Filter Loop

Reduce Loop

Some Loop

Every Loop

Find Loop

Performance is measured with console.time() and console.timeEnd(). The test task moves 50 million items from one array to another, and each loop runs asynchronously to ensure a fair comparison.

console.time('My Description');
// Code to measure
console.timeEnd('My Description');

The array used for the test is created as follows:

console.time('Array Creation');
const numbersList = Array.from({ length: 50_000_000 }, () => Math.floor(Math.random() * 100));
console.timeEnd('Array Creation');

All loops are executed in an async IIFE:

(async () => {
  await usingForLoop(numbersList);
  await usingWhile(numbersList);
  await usingDoWhile(numbersList);
  await usingForOf(numbersList);
  await usingForEach(numbersList);
  await usingMap(numbersList);
  await usingFilter(numbersList);
  await usingReduce(numbersList);
  await usingSome(numbersList);
  await usingEvery(numbersList);
  await usingFind(numbersList);
})();

Loop Implementations

For Loop

const usingForLoop = async (array) => {
  console.time('FOR LOOP');
  const newNumbersList = [];
  for (let i = 0; i < array.length; i++) {
    newNumbersList.push(array[i]);
  }
  console.timeEnd('FOR LOOP');
};

While Loop

const usingWhile = async (array) => {
  console.time('WHILE');
  let i = 0;
  const newNumbersList = [];
  while (i < array.length) {
    newNumbersList.push(array[i]);
    i++;
  }
  console.timeEnd('WHILE');
};

Do‑While Loop

const usingDoWhile = async (array) => {
  console.time('DO WHILE');
  let i = 0;
  const newNumbersList = [];
  do {
    newNumbersList.push(array[i]);
    i++;
  } while (i < array.length);
  console.timeEnd('DO WHILE');
};

For‑Of Loop

const usingForOf = async (array) => {
  console.time('FOR OF');
  const newNumbersList = [];
  for (const item of array) {
    newNumbersList.push(item);
  }
  console.timeEnd('FOR OF');
};

forEach Loop

const usingForEach = async (array) => {
  console.time('FOR EACH');
  const newNumbersList = [];
  array.forEach((item) => newNumbersList.push(item));
  console.timeEnd('FOR EACH');
};

Map Loop

const usingMap = async (array) => {
  console.time('MAP');
  const newNumbersList = array.map((number) => number);
  console.timeEnd('MAP');
};

Filter Loop

const usingFilter = async (array) => {
  console.time('FILTER');
  const newNumbersList = array.filter(() => true);
  console.timeEnd('FILTER');
};

Reduce Loop

const usingReduce = async (array) => {
  console.time('REDUCE');
  const newNumbersList = array.reduce((acc, item) => {
    acc.push(item);
    return acc;
  }, []);
  console.timeEnd('REDUCE');
};

Some Loop

const usingSome = async (array) => {
  console.time('SOME');
  const newNumbersList = [];
  array.some((item) => {
    newNumbersList.push(item);
    return false;
  });
  console.timeEnd('SOME');
};

Every Loop

const usingEvery = async (array) => {
  console.time('EVERY');
  const newNumbersList = [];
  array.every((item) => {
    newNumbersList.push(item);
    return true;
  });
  console.timeEnd('EVERY');
};

Find Loop

const usingFind = async (array) => {
  console.time('FIND');
  const newNumbersList = [];
  array.find((item) => {
    newNumbersList.push(item);
    return false;
  });
  console.timeEnd('FIND');
};

Each loop was executed five times and the average timings were recorded. The resulting chart (shown below) indicates the top five fastest methods:

Map

For Loop

While

Do While

For Each

Interestingly, only Map is a function call; the others are explicit loop constructs. The test focused on a single task, so results may vary with different workloads, memory, or CPU configurations. Nevertheless, Map and For Loop consistently showed the best performance, while For‑Of performed surprisingly poorly.

Although Map invokes a callback each iteration, modern JavaScript engines such as V8 heavily optimize high‑order array methods. These optimizations can reduce overhead and predict execution paths, allowing Map to rival or even surpass a traditional for loop.

Conclusion

Based on the benchmark, Map and For Loop have comparable efficiency. Choose the construct that best fits your needs: Map returns a new array but cannot break early, whereas a for loop offers more control.