JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr1 = ['a','b','c'];
var arr2 = arr1.slice();
arr2.push('d');  //now, arr1 = ['a','b','c','d']

document.write(arr1+"<br/>");
document.write(arr2);

document.write("<br/>===== Reference Types<br/>");

var obj1 = { prop : "value" };
var obj2 = { prop : "another" };
var obj3 = { prop : "yet another" };

var arr1 = [ obj1, obj2, obj3 ];
var arr2 = arr1.slice();

arr2.push({ prop : "pushed" });

document.write("arr 1 index 1 = " + arr1[1].prop + "<br/>");

//change that object
obj2.prop = "changed";

document.write("arr2 index 1 = " + arr2[1].prop + "<br/>");