Function groupBy

groupBy<T, TKey>(keySelector): CollectorFunction<T, Map<TKey, T[]>>
Groups the source by a key selector.
Type Parameters
- T
  Type of items in the source.
- TKey
  Type of the key.
Parameters
- keySelector: ((entry: T) => TKey)
  Key selector function.
  - - (entry): TKey
    - Parameters
      entry: T
      Returns TKey
Returns CollectorFunction<T, Map<TKey, T[]>>
Collector that groups the source by a key selector.
Example
```
const result = groupBy<number, string>((x) => x % 2 === 0 ? "even" : "odd")([1, 2, 3, 4]);
console.log(result);
// Map {
//   'odd' => [1, 3],
//   'even' => [2, 4],
// }
```
- Defined in collectors/groupBy/groupBy.ts:21