Run results for: concat vs splice for joining two arrays

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:147.0) Gecko/20100101 Firefox/147.0

Browser: Firefox 147

Operating system: Windows

Device Platform: Desktop

Date tested: 2 months ago

Test name	Executions per second
immutable with concat	30668.6 Ops/sec
direct mutation with splice + spread	5601.4 Ops/sec

Script Preparation code:

var numSamples = 10000
var data = "TEST DATA"
var makeArray = len=> Array(len).fill(data)

Tests:

immutable with concat
const a = makeArray(numSamples) const b = makeArray(numSamples) const results = a.concat(b)
direct mutation with splice + spread
const a = makeArray(numSamples) const b = makeArray(numSamples) a.splice(a.length, 0, ...b);