collectBy
The collectBy function groups elements of an array into subarrays based on a key selector function.
Syntax
typescript
collectBy<T, K extends PropertyKey>(
array: T[],
keySelector: (value: T, index: number) => K
): T[][];Parameters
| Name | Type | Description |
|---|---|---|
array | T[] | Source array |
keySelector | (value: T, index: number) => K | Function to select the grouping key |
Returns
| Type | Description |
|---|---|
T[][] | Subarrays grouped by key |
Examples
typescript
collectBy([1, 2, 3, 4], x => x % 2); // => [[2,4],[1,3]]
collectBy(["a", "b", "aa"], x => x.length); // => [["a","b"],["aa"]]Notes
- Useful for grouping elements by custom criteria.