flatMap
The flatMap function applies a function to each element of an array and "flattens" the result into a new array.
Syntax
typescript
flatMap<T, U>(array: T[], fn: (value: T, index: number, array: T[]) => U | U[]): U[];Parameters
| Name | Type | Description |
|---|---|---|
array | T[] | Source array |
fn | (value: T, index: number, array: T[]) => U | U[] | Mapping function |
Returns
| Type | Description |
|---|---|
U[] | New flattened array |
Examples
typescript
flatMap([1, 2, 3], x => [x, x * 2]); // => [1, 2, 2, 4, 3, 6]
flatMap([1, 2, 3], x => x * 2); // => [2, 4, 6]Notes
- Equivalent to map followed by flat with depth 1.
- Does not modify the original array.