Run results for: merge maps big

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser: Chrome 103

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Merge spread	679.0 Ops/sec
merge foreach	828.4 Ops/sec
merge 2 foreach	884.5 Ops/sec
update big map	10470.4 Ops/sec

Script Preparation code:

const arr = [];
const arr2 = [];
for (let i = 0; i < 10000; i++) {
    arr.push([i, 'Val' + i]);
    arr2.push(['key' + i, 'Val' + i]);
}

var map1 = new Map(arr)
var map2 = new Map(arr2)

const arr3 = [];
for (let i = 0; i < 1000; i++) {
    arr3.push(['key2' + i, 'Val' + i]);
}
var map9 = new Map(arr3)

Tests:

Merge spread
var map3 = new Map([...map1, ...map2]);
merge foreach
var map4 = new Map(map1) map2.forEach((val, key) => {map4.set(key, val)})
merge 2 foreach
var map4 = new Map() map1.forEach((val, key) => {map4.set(key, val)}) map2.forEach((val, key) => {map4.set(key, val)})
update big map
map9.forEach( (val,key) => {map1.set(key,val)})

Run results for: merge maps big

Merge spread

merge foreach

merge 2 foreach

update big map