function duplicates(arr) {
let duplicateObj = new Set()
let result = []
for(let i=0;i<arr.length;i++){
console.log("current element",arr[i],"has is",duplicateObj.has(arr[i]))
if(duplicateObj.has(arr[i])){
result.push(arr[i])
}else{
duplicateObj.add(arr[i])
}
}
let resultSet = new Set(result)
return [...resultSet]
}
console.log(duplicates([1, 2, 4, 4, 3, 3, 1, 5, 3]))