72 lines
2.9 KiB
TypeScript
72 lines
2.9 KiB
TypeScript
/**
|
|
* Reduces an array to a single value using an async reducer function.
|
|
*
|
|
* Applies the reducer function sequentially to each element (left to right),
|
|
* carrying an accumulated result from one call to the next. Unlike other async
|
|
* array methods, reduce must process elements sequentially and does not support
|
|
* concurrency limiting.
|
|
*
|
|
* @template T - The type of elements in the array.
|
|
* @template U - The type of the accumulated result.
|
|
* @param {readonly T[]} array The array to reduce.
|
|
* @param {(accumulator: U, currentValue: T, currentIndex: number, array: readonly T[]) => Promise<U>} reducer An async function that processes each element.
|
|
* @param {U} initialValue The initial value of the accumulator.
|
|
* @returns {Promise<U>} A promise that resolves to the final accumulated value.
|
|
* @example
|
|
* const numbers = [1, 2, 3, 4, 5];
|
|
* const sum = await reduceAsync(
|
|
* numbers,
|
|
* async (acc, n) => acc + await fetchValue(n),
|
|
* 0
|
|
* );
|
|
* // Returns: sum of all fetched values
|
|
*
|
|
* @example
|
|
* const users = [{ id: 1 }, { id: 2 }, { id: 3 }];
|
|
* const userMap = await reduceAsync(
|
|
* users,
|
|
* async (acc, user) => {
|
|
* const details = await fetchUserDetails(user.id);
|
|
* acc[user.id] = details;
|
|
* return acc;
|
|
* },
|
|
* {} as Record<number, any>
|
|
* );
|
|
* // Returns: { 1: {...}, 2: {...}, 3: {...} }
|
|
*/
|
|
declare function reduceAsync<T, U>(array: readonly T[], reducer: (accumulator: U, currentValue: T, currentIndex: number, array: readonly T[]) => Promise<U>, initialValue: U): Promise<U>;
|
|
/**
|
|
* Reduces an array to a single value using an async reducer function.
|
|
*
|
|
* Applies the reducer function sequentially to each element (left to right),
|
|
* carrying an accumulated result from one call to the next. Unlike other async
|
|
* array methods, reduce must process elements sequentially and does not support
|
|
* concurrency limiting.
|
|
*
|
|
* When no initial value is provided, the first element of the array is used as
|
|
* the initial value and the reduction starts from the second element.
|
|
*
|
|
* @template T - The type of elements in the array.
|
|
* @param {readonly T[]} array The array to reduce.
|
|
* @param {(accumulator: T, currentValue: T, currentIndex: number, array: readonly T[]) => Promise<T>} reducer An async function that processes each element.
|
|
* @returns {Promise<T | undefined>} A promise that resolves to the final accumulated value, or undefined if the array is empty.
|
|
* @example
|
|
* const numbers = [1, 2, 3, 4, 5];
|
|
* const sum = await reduceAsync(
|
|
* numbers,
|
|
* async (acc, n) => acc + n
|
|
* );
|
|
* // Returns: 15
|
|
*
|
|
* @example
|
|
* const emptyArray: number[] = [];
|
|
* const result = await reduceAsync(
|
|
* emptyArray,
|
|
* async (acc, n) => acc + n
|
|
* );
|
|
* // Returns: undefined
|
|
*/
|
|
declare function reduceAsync<T>(array: readonly T[], reducer: (accumulator: T, currentValue: T, currentIndex: number, array: readonly T[]) => Promise<T>): Promise<T>;
|
|
|
|
export { reduceAsync };
|