fastify-riotjs-and-lowdb/node_modules/collect.js/docs/api/mapToGroups.md

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],
// }

View source on GitHub