109 lines
2.1 KiB
Markdown
109 lines
2.1 KiB
Markdown
# `groupBy()`
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The groupBy method groups the collection's items into multiple collections by a given key:
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> If you want to group the collection by keys as a plain object, see [mapToGroups](mapToGroups)
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```js
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const collection = collect([
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{
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product: 'Chair',
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manufacturer: 'IKEA',
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},
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{
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product: 'Desk',
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manufacturer: 'IKEA',
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},
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{
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product: 'Chair',
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manufacturer: 'Herman Miller',
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},
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]);
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const grouped = collection.groupBy('manufacturer');
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grouped.all();
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// {
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// IKEA: Collection {
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// items: [
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// {
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// id: 100,
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// product: 'Chair',
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// manufacturer: 'IKEA',
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// price: '1490 NOK',
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// },
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// {
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// id: 150,
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// product: 'Desk',
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// manufacturer: 'IKEA',
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// price: '900 NOK',
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// },
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// ],
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// },
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// 'Herman Miller': Collection {
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// items: [
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// {
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// id: 200,
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// product: 'Chair',
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// manufacturer: 'Herman Miller',
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// price: '9990 NOK',
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// },
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// ],
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// },
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// }
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```
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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:
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```js
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const collection = collect([
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{
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product: 'Chair',
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manufacturer: 'IKEA',
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},
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{
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product: 'Desk',
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manufacturer: 'IKEA',
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},
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{
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product: 'Chair',
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manufacturer: 'Herman Miller',
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},
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]);
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const grouped = collection.groupBy((item, key) => item.manufacturer.substring(0, 3));
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grouped.all();
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// {
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// IKE: Collection {
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// items: [
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// {
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// id: 100,
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// product: 'Chair',
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// manufacturer: 'IKEA',
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// price: '1490 NOK',
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// },
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// {
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// id: 150,
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// product: 'Desk',
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// manufacturer: 'IKEA',
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// price: '900 NOK',
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// },
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// ],
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// },
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// Her: Collection {
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// items: [
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// {
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// id: 200,
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// product: 'Chair',
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// manufacturer: 'Herman Miller',
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// price: '9990 NOK',
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// },
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// ],
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// },
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// }
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```
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[View source on GitHub](https://github.com/ecrmnn/collect.js/blob/master/src/methods/groupBy.js) |