@silyze/resolver

A minimal wrapper around Promise.withResolvers() with a built-in polyfill for environments that do not yet support the native API.

This utility allows you to obtain a promise, resolve, and reject object in a clean and consistent way.

Features

• Uses native Promise.withResolvers() when available (Node 22+, modern browsers)
• Falls back to a spec-compliant polyfill when not available
• Type-safe with full TypeScript support
• Lightweight and dependency-free
• Supports both CommonJS and ES Modules

Installation

npm install @silyze/resolver

Usage

import createResolver from "@silyze/resolver";

const { promise, resolve, reject } = createResolver<number>();

setTimeout(() => resolve(42), 1000);

const result = await promise; // 42

API

createResolver<T>(): ResolverWithPromise<T>

Returns an object with the following properties:

| Property | Type | Description | | | --------- | ------------------------ | ------------------------------------------ | -------------------- | | promise | Promise<T> | The promise that can be awaited or chained | | | resolve | `(value: T | PromiseLike) => void` | Resolves the promise | | reject | (error: Error) => void | Rejects the promise | |

Example

const { promise, resolve, reject } = createResolver<string>();

someStream.on("data", resolve);
someStream.on("error", reject);

try {
  const data = await promise;
  console.log("Received:", data);
} catch (err) {
  console.error("Stream failed:", err);
}

Polyfill Behavior

If Promise.withResolvers() is not available, this package will fall back to an internal implementation using new Promise().

Compatibility

| Environment | Native Support | Works with @silyze/resolver | | --------------- | -------------- | --------------------------- | | Node.js 22+ | Yes | Yes (uses native) | | Node.js 14–21 | No | Yes (uses polyfill) | | Modern Browsers | Yes | Yes | | Older Browsers | No | Yes |

Type Definitions

export type Resolver<T> = {
  resolve: (value: T | PromiseLike<T>) => void;
  reject: (error: Error) => void;
};

export type ResolverWithPromise<T> = Resolver<T> & {
  promise: Promise<T>;
};