Run results for: Array.find vs. Map.get

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.0

Device Platform: Mobile

Date tested: 2 years ago

Map.get, 10 000 elements

4.9M/s

Map.get, 1 000 000 elements

4.6M/s

Array.find, 10 000 elements

142K/s

Array.find, 10 lookups

12K/s

Array to Map + Map.get, 1 lookup

2K/s

Array to Map + Map.get, 10 lookups

2K/s

Array to Map + Map.get, 100 lookups

2K/s

Array.find, 1 000 000 elements

1K/s

Array.find, 100 lookups

1K/s

View exact numbers

Test name	Executions per second
✓ Map.get, 10 000 elements	4,919,680 Ops/sec
Map.get, 1 000 000 elements	4,596,050 Ops/sec
Array.find, 10 000 elements	141,608 Ops/sec
Array.find, 10 lookups	11,887 Ops/sec
Array to Map + Map.get, 1 lookup	2,498 Ops/sec
Array to Map + Map.get, 10 lookups	2,473 Ops/sec
Array to Map + Map.get, 100 lookups	2,279 Ops/sec
Array.find, 1 000 000 elements	1,293 Ops/sec
Array.find, 100 lookups	1,184 Ops/sec

Script Preparation code:

function getRandomElement(id) {
  return {
    id,
    a: Math.random(),
    b: Math.random(),
    c: Math.random(),
  }
}

function getArray(length) {
  const result = [];
  for (let i = 0; i < length; i++) {
    result.push(getRandomElement(i))
  }
  
  return result;
}

function arrayToMap(array) {
  return new Map(array.map(el => [el.id, el]));
}

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

array_small = getArray(10000);
array_large = getArray(1000000);

map_small = arrayToMap(array_small);
map_large = arrayToMap(array_large);

Tests:

Array.find, 10 000 elements
const target = getRandomInt(9999); array_small.find(el => el.id === target);
Map.get, 10 000 elements
const target = getRandomInt(9999); map_small.get(target);
Array.find, 1 000 000 elements
const target = getRandomInt(999999); array_large.find(el => el.id === target);
Map.get, 1 000 000 elements
const target = getRandomInt(999999); map_large.get(target)
Array to Map + Map.get, 1 lookup
const map = arrayToMap(array_small); const target = getRandomInt(9999); map.get(target);
Array to Map + Map.get, 10 lookups
const map = arrayToMap(array_small); for (let i = 0; i < 10; i++) { const target = getRandomInt(9999); map.get(target); }
Array to Map + Map.get, 100 lookups
const map = arrayToMap(array_small); for (let i = 0; i < 100; i++) { const target = getRandomInt(9999); map.get(target); }
Array.find, 10 lookups
for (let i = 0; i < 10; i++) { const target = getRandomInt(9999); array_small.find(el => el.id === target) }
Array.find, 100 lookups
for (let i = 0; i < 100; i++) { const target = getRandomInt(9999); array_small.find(el => el.id === target) }