# unique()
The unique method returns all of the unique items in the collection:
const collection = collect([1, 1, 1, 2, 3, 3]);
const unique = collection.unique();
unique.all();
// [1, 2, 3]
When dealing with an array of objects, you may specify the key used to determine uniqueness:
const collection = collect([
{ name: 'iPhone 6', brand: 'Apple', type: 'phone' },
{ name: 'iPhone 5', brand: 'Apple', type: 'phone' },
{ name: 'Apple Watch', brand: 'Apple', type: 'watch' },
{ name: 'Galaxy S6', brand: 'Samsung', type: 'phone' },
{ name: 'Galaxy Gear', brand: 'Samsung', type: 'watch' },
]);
const unique = collection.unique('brand');
unique.all();
// [
// { name: 'iPhone 6', brand: 'Apple', type: 'phone' },
// { name: 'Galaxy S6', brand: 'Samsung', type: 'phone' },
// ]
You may also pass your own callback to determine item uniqueness:
const collection = collect([
{ name: 'iPhone 6', brand: 'Apple', type: 'phone' },
{ name: 'iPhone 5', brand: 'Apple', type: 'phone' },
{ name: 'Apple Watch', brand: 'Apple', type: 'watch' },
{ name: 'Galaxy S6', brand: 'Samsung', type: 'phone' },
{ name: 'Galaxy Gear', brand: 'Samsung', type: 'watch' },
]);
const unique = collection.unique(item => item.brand + item.type);
unique.all();
// [
// { name: 'iPhone 6', brand: 'Apple', type: 'phone' },
// { name: 'Apple Watch', brand: 'Apple', type: 'watch' },
// { name: 'Galaxy S6', brand: 'Samsung', type: 'phone' },
// { name: 'Galaxy Gear', brand: 'Samsung', type: 'watch' },
// ]