export interface Defer<T = any> {
  resolve(value?: T | PromiseLike<T>): void;
  reject(reason?: any): void;
  promise(): Promise<T>;
}

export function createDefer<T = any>(): Defer<T> {
  const r: any = {};
  const promise = new Promise<T>((resolve, reject) => {
    r.resolve = resolve;
    r.reject = reject;
  });

  r.promise = () => promise;

  return r;
}