Function flatMap

flatMap<const Ar extends readonly unknown[], B>(
array: Ar,
mapFn: (a: Ar[number], index: ArrayIndex<Ar>) => readonly B[],
): readonly B[]

Maps each element and flattens the result.

Type Parameters

const Ar extends readonly unknown[]
B

Parameters

array: Ar
mapFn: (a: Ar[number], index: ArrayIndex<Ar>) => readonly B[]

Returns readonly B[]

Example

const words = ['Ada', 'AI'] as const;

const characters = Arr.flatMap(words, (word) => word.split(''));
const labeled = Arr.flatMap<string, string>((word, index) =>
  word.split('').map((char) => `${index}-${char}`),
)(words);

assert.deepStrictEqual(characters, ['A', 'd', 'a', 'A', 'I']);
assert.deepStrictEqual(labeled, ['0-A', '0-d', '0-a', '1-A', '1-I']);

flatMap<A, B>(
mapFn: (a: A, index: Uint32) => readonly B[],
): (array: readonly A[]) => readonly B[]

Maps each element and flattens the result.

Type Parameters

Parameters

mapFn: (a: A, index: Uint32) => readonly B[]

Returns (array: readonly A[]) => readonly B[]

Example

const words = ['Ada', 'AI'] as const;

const characters = Arr.flatMap(words, (word) => word.split(''));
const labeled = Arr.flatMap<string, string>((word, index) =>
  word.split('').map((char) => `${index}-${char}`),
)(words);

assert.deepStrictEqual(characters, ['A', 'd', 'a', 'A', 'I']);
assert.deepStrictEqual(labeled, ['0-A', '0-d', '0-a', '1-A', '1-I']);

Function flatMap

Type Parameters

Parameters

Returns readonly B[]

Example

Type Parameters

Parameters

Returns (array: readonly A[]) => readonly B[]

Example

Settings