JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" id="button" value="Button" />

JavaScript

var ar = [0,1,2,3,4,5], count = 0, randomNos = {};
    document.getElementById('button').onclick = function(){
        no = Math.floor(Math.random()*ar.length);
        while(count <= ar.length){
            no = Math.floor(Math.random()*ar.length);
            
            if(randomNos[no]){
                count++
            }
            else{
                randomNos[no] = 1;
                break;
            }
        }
        if(count > ar.length){
            count = 0;
            randomNos = {}
        }
        alert(ar[no]);
    };