Run results for: new Map vs set array to map

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Browser: Firefox 135

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

push array to map

1722.8M/s

new Map

86K/s

View exact numbers

Test name	Executions per second
✓ push array to map	1,722,795,136 Ops/sec
new Map	85,952 Ops/sec

Script Preparation code:

var arr = [];

for (let i = 1; i <= 100; i++) {
  arr.push({ id: i, name: `${i}` });
}

var arr2 = [];

for (let i = 101; i <= 200; i++) {
  arr.push({ id: i, name: `${i}` });
}

var map = new Map(arr.map(item => [item.id, item]));

Tests:

new Map
const map2 = new Map(arr2.map(item => [item.id, item])); map = new Map([...map, ...arr2.map(item => [item.id, item])]);
push array to map
arr2.forEach(item => { map.set([item.id, item]) });

Run results for: new Map vs set array to map

What is faster create new Map from two maps or set array items to map?

new Map

push array to map