livekit-client/src/utils/TypedPromise.ts

JavaScript/TypeScript client SDK for LiveKit

type InferErrors<T> = T extends TypedPromise<any, infer E> ? E : never;

export default class TypedPromise<T, E extends Error> extends Promise<T> {
  // eslint-disable-next-line @typescript-eslint/no-useless-constructor
  constructor(
    executor: (resolve: (value: T | PromiseLike<T>) => void, reject: (reason: E) => void) => void,
  ) {
    super(executor);
  }

  catch<TResult = never>(
    onrejected?: ((reason: E) => TResult | PromiseLike<TResult>) | null | undefined,
  ): TypedPromise<T | TResult, E> {
    return super.catch(onrejected);
  }

  static resolve: {
    (): TypedPromise<void, never>;
    <V>(value: V): TypedPromise<Awaited<V>, never>;
  } = <V>(value?: V): TypedPromise<Awaited<V>, never> => {
    return super.resolve(value) as TypedPromise<Awaited<V>, never>;
  };

  static reject<E extends Error>(reason: E): TypedPromise<never, E> {
    return super.reject(reason);
  }

  static all<T extends readonly unknown[] | []>(
    values: T,
  ): TypedPromise<{ -readonly [P in keyof T]: Awaited<T[P]> }, InferErrors<T[number]>> {
    return super.all(values) as any;
  }

  static race<T extends readonly (TypedPromise<any, any> | any)[]>(
    values: T,
  ): TypedPromise<
    T[number] extends TypedPromise<infer U, any>
      ? U
      : T[number] extends PromiseLike<infer U>
        ? U
        : Awaited<T[number]>,
    InferErrors<T[number]>
  > {
    return super.race(values);
  }
}