@thisisagile/easy/src/utils/Promise.ts

Straightforward library for building domain-driven microservice architectures

import { toArray } from '../types/Array';
import { ErrorOrigin } from '../types/ErrorOrigin';
import { List, toList } from '../types/List';
import { asString } from '../types/Text';

type Pro<A> = A | PromiseLike<A>;
type Aw<A> = Awaited<A>;

export const resolve = <S = unknown>(subject: S | PromiseLike<S>): Promise<S> => Promise.resolve(subject);
export const reject = <S = never>(e: ErrorOrigin): Promise<S> => Promise.reject(e);

export const tuple = {
  2: <F, S>(first: Pro<F>, second: Pro<S>): Promise<[Aw<F>, Aw<S>]> => Promise.all([first, second]),
  3: <F, S, T>(first: Pro<F>, second: Pro<S>, third: Pro<T>): Promise<[Aw<F>, Aw<S>, Aw<T>]> => Promise.all([first, second, third]),
  4: <F, S, T, Fo>(first: Pro<F>, second: Pro<S>, third: Pro<T>, forth: Pro<Fo>): Promise<[Aw<F>, Aw<S>, Aw<T>, Aw<Fo>]> =>
    Promise.all([first, second, third, forth]),
  5: <F, S, T, Fo, Fi>(first: Pro<F>, second: Pro<S>, third: Pro<T>, forth: Pro<Fo>, fifth: Pro<Fi>): Promise<[Aw<F>, Aw<S>, Aw<T>, Aw<Fo>, Aw<Fi>]> =>
    Promise.all([first, second, third, forth, fifth]),
  all: <F, S>(first: Pro<F>, second: Pro<S>[]): Promise<[Aw<F>, Aw<S[]>]> => Promise.all([first, Promise.all(second)]),
  spread: <F, S>(first: Pro<F>, ...second: Pro<S>[]): Promise<[Aw<F>, Aw<S[]>]> => Promise.all([first, Promise.all(toArray(second))]),
  list: <T>(list: Pro<T>[]): Promise<List<Aw<T>>> => Promise.all([...list]).then(toList),
  settled: <T>(list: Pro<T>[]): Promise<{ fulfilled: List<Aw<T>>; rejected: List<string> }> =>
    Promise.allSettled([...list]).then(rs => ({
      fulfilled: toList(...rs.filter(r => r.status === 'fulfilled').map(r => r.value)),
      rejected: toList(...rs.filter(r => r.status === 'rejected').map(r => asString(r.reason))),
    })),
};

export const tuple2 = tuple[2];
export const tuple3 = tuple[3];
export const tuple4 = tuple[4];
export const tuple5 = tuple[5];
export const settled = tuple.settled;