AsyncIteratorUtilities.ts

AsyncIteratorUtilities.ts

 export const map = <T, O>(map: (input: T) => Promise<O> | O) =>
    async function* mapGenerator(asyncIterable: AsyncIterableIterator<T>) {
      for await (const value of asyncIterable) {
        yield map(value);
      }
    };

export const filter = <T, U extends T>(filter: (input: T) => input is U) =>
    async function* filterGenerator(asyncIterable: AsyncIterableIterator<T>) {
      for await (const value of asyncIterable) {
        if (filter(value)) {
          yield value;
        }
      }
    };