Remove Duplicates From Array

Example

Input:

1[1, 2, 2, 3, 3, 3, 4, 4, 4, 5, 6, 6, 6];

Output:

1[1, 2, 3, 4, 5, 6];

Solution

Use filter and indexOf

1function removeDuplicatesFromArray(input) {
2  return input.filter((item, index) => input.indexOf(item) == index);
3}

Use object to mark if an item has appeared

1function removeDuplicatesFromArray(input) {
2  var unique = {};
3
4  input.forEach(item => {
5    if (!unique[item]) {
6      unique[item] = true;
7    }
8  });
9
10  return Object.keys(unique);
11}

Create an array from Set

1function removeDuplicatesFromArray(input) {
2  return Array.from(new Set(input));
3}