Run results for: map foreach vs array lookup vs map const of vs arr const of

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:92.0) Gecko/20100101 Firefox/92.0

Browser: Firefox 92

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
arr to map lookup	2781.0 Ops/sec
map foreach	13184.6 Ops/sec
map const of	5397.9 Ops/sec
arr const of	17832.9 Ops/sec

Script Preparation code:

var arr = [];
var map = new Map();

for (let i = 0; i < 12000; i++) {
  const num = i * 7 + Math.ceil(Math.random() * 5); 
  const str = (Math.random() + 1).toString(36).substring(7);
  arr.push(num);
  map.set(num, str);
}

Tests:

arr to map lookup
for (let i = 0;i < arr.length; i++) { let num = arr[i]; let str = map.get(num) || ''; }
map foreach
map.forEach((el)=>{})
map const of
for (const str of map) { let str32 = str[1]}
arr const of
for (const str of arr) { let str32 = str}

Run results for: map foreach vs array lookup vs map const of vs arr const of

arr to map lookup

map foreach

map const of

arr const of