Run results for: merge array without duplicates - spread&new Set vs foreach&findIndex

Run details:

User agent: Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4458.0 Mobile Safari/537.36

Browser: Chrome Mobile 91

Operating system: Android 6.0

Device Platform: Mobile

Date tested: 3 years ago

Test name	Executions per second
forEach, findIndex, push	59.9 Ops/sec
spread, new Set	189.9 Ops/sec

Script Preparation code:

var arr = [];
var i = 0;
var copies = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]; // length 14
var result1 = [];
var result2 = [];

while (i <= 1E5) arr[i] = i++;

Tests:

forEach, findIndex, push
arr.forEach(item => { if(copies.findIndex(copy => copy === item) === -1){ result1.push(item); } });
spread, new Set
result2 = [...new Set([...arr,...copies])];

Run results for: merge array without duplicates - spread&new Set vs foreach&findIndex

Measuring which is faster

forEach, findIndex, push

spread, new Set