Run results for: Iteration Array for-of vs Map for-of 4

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36

Browser: Chrome 129

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Array for-of

8.2M/s

Map for-of

3.9M/s

View exact numbers

Test name	Executions per second
✓ Array for-of	8,235,080 Ops/sec
Map for-of	3,917,427 Ops/sec

Script Preparation code:

var obj = {
  a: 1,
  b: 2,
  c: 3,
  d: 4,
  e: 5,
  f: 6,
  g: 7,
  h: 8,
  i: 9,
  j: 10,
  k: 11,
  l: 12,
  m: 13,
  n: 14,
  o: 15,
  p: 16,
  q: 17,
  r: 18,
  s: 19,
  t: 20,
  u: 21,
  v: 22,
  w: 23,
  x: 24,
  y: 25,
  z: 26
};
var map = new Map(Object.entries(obj));

var array = [
  ["a", 1], 
  ["b", 2], 
  ["c", 3], 
  ["d", 4], 
  ["e", 5], 
  ["f", 6], 
  ["g", 7], 
  ["h", 8], 
  ["i", 9], 
  ["j", 10], 
  ["k", 11], 
  ["l", 12], 
  ["m", 13], 
  ["n", 14], 
  ["o", 15], 
  ["p", 16], 
  ["q", 17], 
  ["r", 18], 
  ["s", 19], 
  ["t", 20], 
  ["u", 21], 
  ["v", 22], 
  ["w", 23], 
  ["x", 24], 
  ["y", 25], 
  ["z", 26], 
];

Tests:

Array for-of
let total = 0; for(const item of array){ total += item[1]; }
Map for-of
let total = 0; for (const [key, value] of map) { total += value; }