CareerCup

store the data from array to set

1)
Sort the array nlogn
scan the sorted array using two indices and element duplicates between two indices
Runtime O(nlogn), space O(1)

2)
hash array elements as key to a hash-table, output the keys in the hashtable
Runtime O(n), space -- depends on hash-table, assuming typical, O(n)

You can use Set .. in which we have add() method which returns false if element is already present in the Set..

function remove_duplicates(arr) {
	const store = {};
	let ptr = 0;

	for (let index=0; index<arr.length; index++) {
		if (!store[arr[index]]) {
			store[arr[index]] = true;
			if (index !== ptr)
				arr[ptr] = arr[index];
			ptr++;
		}
	}

	return arr.slice(0, ptr);
}