# groupBy()
The groupBy method groups the collection's items into multiple collections by a given key:
If you want to group the collection by keys as a plain object, see mapToGroups
const collection = collect([
{
product: 'Chair',
manufacturer: 'IKEA',
},
{
product: 'Desk',
manufacturer: 'IKEA',
},
{
product: 'Chair',
manufacturer: 'Herman Miller',
},
]);
const grouped = collection.groupBy('manufacturer');
grouped.all();
// {
// IKEA: Collection {
// items: [
// {
// id: 100,
// product: 'Chair',
// manufacturer: 'IKEA',
// price: '1490 NOK',
// },
// {
// id: 150,
// product: 'Desk',
// manufacturer: 'IKEA',
// price: '900 NOK',
// },
// ],
// },
// 'Herman Miller': Collection {
// items: [
// {
// id: 200,
// product: 'Chair',
// manufacturer: 'Herman Miller',
// price: '9990 NOK',
// },
// ],
// },
// }
In addition to passing a string key, you may also pass a callback. The callback should return the value you wish to key the group by:
const collection = collect([
{
product: 'Chair',
manufacturer: 'IKEA',
},
{
product: 'Desk',
manufacturer: 'IKEA',
},
{
product: 'Chair',
manufacturer: 'Herman Miller',
},
]);
const grouped = collection.groupBy((item, key) => item.manufacturer.substring(0, 3));
grouped.all();
// {
// IKE: Collection {
// items: [
// {
// id: 100,
// product: 'Chair',
// manufacturer: 'IKEA',
// price: '1490 NOK',
// },
// {
// id: 150,
// product: 'Desk',
// manufacturer: 'IKEA',
// price: '900 NOK',
// },
// ],
// },
// Her: Collection {
// items: [
// {
// id: 200,
// product: 'Chair',
// manufacturer: 'Herman Miller',
// price: '9990 NOK',
// },
// ],
// },
// }