JSFiddle - React, Tailwind, and code Playground

HTML

<p>
In arr :
<span id="testarr">
</span></p>
<p>
In clone :
<span id="testclone">
</span>
</p>
<p>
Deep In arr :
<span id="testarrdeep">
</span></p>
<p>
Deep In clone :
<span id="testclonedeep">
</span>
</p>

JavaScript

var arr = [{'obj1':1}, {'obj2':2}];
var clone2 = JSON.parse(JSON.stringify(arr));
clone2[0].test = "defined";
$("#testarrdeep").html(arr[0].test);
$("#testclonedeep").html(clone2[0].test);
var clone = arr.slice(0);
clone[0].test = "defined";
$("#testarr").html(arr[0].test);
$("#testclone").html(clone[0].test);