mapToGroups()
The mapToGroups method iterates through the collection and passes each value to the given callback:
const collection = collect([
{ id: 1, name: 'A' },
{ id: 2, name: 'B' },
{ id: 3, name: 'C' },
{ id: 4, name: 'B' },
]);
const groups = collection.mapToGroups((item, key) => [item.name, item.id]);
// {
// A: [1],
// B: [2, 4],
// C: [3],
// }