// Primitives
const unique = (arr) => [...new Set(arr)];
// Objects — deduplicate by key
const uniqueBy = (arr, key) => {
const seen = new Set();
return arr.filter((item) => {
const k = typeof key === 'function' ? key(item) : item[key];
return seen.has(k) ? false : seen.add(k);
});
};
// Usage
console.log(unique([1, 2, 2, 3, 3, 3])); // [1, 2, 3]
const users = [{ id: 1 }, { id: 2 }, { id: 1 }];
console.log(uniqueBy(users, 'id')); // [{ id: 1 }, { id: 2 }]Create a free account and build your private vault. Share publicly whenever you want.