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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.54 Safari/537.36

Browser: Chrome 95

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Array.find, 10 000 elements	83460.8 Ops/sec
Map.get, 10 000 elements	2225462.0 Ops/sec
Array.find, 1 000 000 elements	143.6 Ops/sec
Map.get, 1 000 000 elements	2221160.5 Ops/sec
Array to Map + Map.get, 1 lookup	1380.2 Ops/sec
Array to Map + Map.get, 10 lookups	1570.5 Ops/sec
Array to Map + Map.get, 100 lookups	1514.5 Ops/sec
Array.find, 10 lookups	9394.8 Ops/sec
Array.find, 100 lookups	701.5 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) }

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

Test the performance of Array.find vs. Map.get, with various array sizes, and with/without conversion from array to map

Array.find, 10 000 elements

Map.get, 10 000 elements

Array.find, 1 000 000 elements

Map.get, 1 000 000 elements

Array to Map + Map.get, 1 lookup

Array to Map + Map.get, 10 lookups

Array to Map + Map.get, 100 lookups

Array.find, 10 lookups

Array.find, 100 lookups