Run results for: Lodash flatten vs native js

Run details:

User agent: Mozilla/5.0 (Linux; Android 9; SM-J730F) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Mobile Safari/537.36 OPR/64.2.3282.60128

Browser: Opera Mobile 64

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
native 1	112696.3 Ops/sec
native 2	134158.2 Ops/sec
Native(ES2019)	85197.1 Ops/sec
flatMap	81578.5 Ops/sec
_.flatten	161824.4 Ops/sec

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

const arr = [1, [2, [3, [4]], 5]];

Tests:

native 1
[1, [2, [3, [4]], 5]].reduce( (a, b) => a.concat(b), [])
native 2
[].concat(...[1, [2, [3, [4]], 5]])
Native(ES2019)
[1, [2, [3, [4]], 5]].flat()
flatMap
[1, [2, [3, [4]], 5]].flatMap(number => number)
_.flatten
_.flatten([1, [2, [3, [4]], 5]])

Run results for: Lodash flatten vs native js

native 1

native 2

Native(ES2019)

flatMap

_.flatten