Run results for: Create Map/Set vs reuse Map/Set

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Safari/537.36

Browser: Chrome 89

Operating system: Mac OS X 11.2.3

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Create Map	41799.6 Ops/sec
Create Set	48872.5 Ops/sec
Reuse Map	25036.0 Ops/sec
Reuse Set	25403.8 Ops/sec

Script Preparation code:

var list = Array(500).fill(1).map((x, i) => x + i);
var entries = list.map(x => [x, true]);

var globalMap = new Map();
var globalSet = new Set();

Tests:

Create Map
var map = new Map(entries);
Create Set
var set = new Set(list);
Reuse Map
globalMap.clear(); entries.forEach(x => globalMap.set(x[0], x[1]));
Reuse Set
globalSet.clear(); list.forEach(x => globalSet.add(x));

Run results for: Create Map/Set vs reuse Map/Set

Create Map

Create Set

Reuse Map

Reuse Set