Run results for: union and native , add item to array without duple

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36

Browser: Chrome 83

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
_.union	1184646.0 Ops/sec
native	3201931.0 Ops/sec

HTML Preparation code:

<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js"></script>

Script Preparation code:

var a = [1, 2, 3, 4, 5]
var b = 3

Tests: