Run results for: Array vs object literal v2

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser: Chrome 97

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
map	69.7 Ops/sec
array	67.5 Ops/sec

Script Preparation code:

function setup() {

  const randInt = (min, max) =>
      Math.floor(Math.random() * (max - min + 1) + min);

  const itemMap = {};
  const itemArr = [];

  for (let i = 0; i < 10000; i++) {
      const item = {
          id: randInt(0, 1000000),
          value: `value-${randInt(0, 1000000)}`
      };
      itemArr.push(item);
      itemMap[item.id] = item;
  }

  const itemIdsToGet = [itemArr[8002].id, itemArr[2423].id, itemArr[5322].id, itemArr[3].id, itemArr[7242].id]
  
  return {
    itemIdsToGet,
    itemMap,
    itemArr
  }
}

​x
 
function setup() {​  const randInt = (min, max) =>      Math.floor(Math.random() * (max - min + 1) + min);​  const itemMap = {};  const itemArr = [];​  for (let i = 0; i < 10000; i++) {      const item = {          id: randInt(0, 1000000),          value: `value-${randInt(0, 1000000)}`      };      itemArr.push(item);      itemMap[item.id] = item;  }​  const itemIdsToGet = [itemArr[8002].id, itemArr[2423].id, itemArr[5322].id, itemArr[3].id, itemArr[7242].id]    return {    itemIdsToGet,    itemMap,    itemArr  }}

Tests:

map

const values = setup();

for  (const itemIdToUpdate of values.itemIdsToGet) {
  values.itemMap[itemIdToUpdate].value = 'updated'
}

 
const values = setup();​for  (const itemIdToUpdate of values.itemIdsToGet) {  values.itemMap[itemIdToUpdate].value = 'updated'}

array

const values = setup();

for  (const itemIdToUpdate of values.itemIdsToGet) {
  const index = values.itemArr.findIndex(x => x.id === itemIdToUpdate);
  
  values.itemArr[index].value = 'updated';

}

 
const values = setup();​for  (const itemIdToUpdate of values.itemIdsToGet) {  const index = values.itemArr.findIndex(x => x.id === itemIdToUpdate);    values.itemArr[index].value = 'updated';​}