JSFiddle - React, Tailwind, and code Playground

by Alexandru Mihai

JavaScript

var arr = [1,2,3,4,2];
var hash = {};
for(i=0;i< arr.length; i++){
	if(!hash[arr[i]])
  		hash[arr[i]] = 1;
   else{
   		console.log(arr[i]);
    	break;
   }
}