@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

``bash
npm install @silyze/resolver
`

Usage

`ts
import createResolver from "@silyze/resolver";

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

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

const result = await promise; // 42
`

API

$3

Returns an object with the following properties:

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

$3

`ts
const { promise, resolve, reject } = createResolver();

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().

$3

| 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

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

export type ResolverWithPromise = Resolver & {
promise: Promise;
};
``