flatMapDeep

Applies an iteratee function to each element of the array and flattens the result to all depths.

Behaves the same as arr.map.flat(Infinity) but with better performance.

Code

🔗 View source code

Benchmark

• hz: Operations per second
• mean: Average response time (ms)

Name	hz	mean	Performance
modern-kit/flatMapDeep	251,685.91	0.0040	fastest
lodash/flatMapDeep.map	184,467.29	0.0054	-
js built-in/map.flat	57,011.35	0.0175	slowest

• modern-kit/flatMapDeep
  • 1.35x faster than lodash/flatMapDeep.map
  • 4.41x faster than js built-in/map.flat

Interface

typescript

/**
 * @description A utility type that recursively unwraps nested array types to extract the innermost element type
 */
type ExtractNestedArrayType<T> = T extends readonly (infer U)[]
  ? ExtractNestedArrayType<U>
  : T;

typescript

function flatMapDeep<T, U>(
  arr: T[] | readonly T[],
  iteratee: (item: ExtractNestedArrayType<T>) => U
): U[];

Usage

typescript

import { flatMapDeep } from '@modern-kit/utils';

const arr = [1, 2, [3, 4, [5, 6]]];
flatMapDeep(arr, (item) => ({ id: item }));
// [{ id: 1}, { id: 2}, { id: 3}, { id: 4}, { id: 5}, { id: 6}];