Run results for: Map iteration comparing

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser: Chrome 135

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Map - for of kv

1.7M/s

Map - while on iterator

1.5M/s

Map - forEach

1.3M/s

View exact numbers

Test name	Executions per second
✓ Map - for of kv	1,697,903 Ops/sec
Map - while on iterator	1,454,957 Ops/sec
Map - forEach	1,263,089 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));

Tests:

Map - for of kv
let total = 0; for (const [key, value] of map) { total += value; }
Map - forEach
let total = 0; map.forEach(function(value, key) { total += value; });
Map - while on iterator
let total = 0; const itr = map.entries(); let entry = itr.next(); while( !entry.done) { total+= entry.value.value; entry = itr.next(); }