/**
 * Simple implementation of the deferred pattern.
 * An object that exposes a promise and functions to resolve and reject it.
 */
export class Deferred<T> {
  resolve: (value?: T | PromiseLike<T>) => void;
  reject: (err?: any) => void;

  promise = new Promise<T>((resolve, reject) => {
    this.resolve = resolve;
    this.reject = reject;
  });
}

export async function pSeries<T>(tasks: Iterable<() => Promise<T> | T>): Promise<T[]> {
  const results = [] as T[];

  for (const task of tasks) {
    results.push(await task());
  }

  return results;
}