Run results for: set.add vs array.push vs map.set

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Safari/605.1.15

Browser: Safari 17

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

set.add

2.8M/s

map.set overwrite

2.8M/s

conditional array.push

1.3M/s

View exact numbers

Test name	Executions per second
✓ set.add	2,846,469 Ops/sec
map.set overwrite	2,841,010 Ops/sec
conditional array.push	1,294,096 Ops/sec

Script Preparation code:

var array = [];
var set = new Set();
var map = new Map();

var existingItem1 = {};
var existingItem2 = {};
var existingItem3 = {};
var newItem1 = {};
var newItem2 = {};
var newItem3 = {};

for (let i = 0, item; i < 100; i++) {
  item = {index: i};
  array.push(item);
  set.add(item);
  map.set(item, 0);
}

array.push(existingItem1, existingItem2, existingItem3);
set.add(existingItem1); set.add(existingItem2); set.add(existingItem3);
map.set(existingItem1, 0); map.set(existingItem2, 0); map.set(existingItem3, 0);

Tests:

conditional array.push
if (!array.includes(existingItem1)) { array.push(existingItem1); } if (!array.includes(newItem1)) { array.push(newItem1); } if (!array.includes(existingItem2)) { array.push(existingItem2); } if (!array.includes(newItem2)) { array.push(newItem2); } if (!array.includes(existingItem3)) { array.push(existingItem3); } if (!array.includes(newItem3)) { array.push(newItem3); }
set.add
set.add(existingItem1); set.add(newItem1); set.add(existingItem2); set.add(newItem2); set.add(existingItem3); set.add(newItem3);
map.set overwrite
map.set(existingItem1, 0); map.set(newItem1, 0); map.set(existingItem2, 0); map.set(newItem2, 0); map.set(existingItem3, 0); map.set(newItem3, 0);