@bun-win32/winmm

Zero-dependency, zero-overhead Win32 WinMM bindings for Bun on Windows.

Overview

@bun-win32/winmm exposes the winmm.dll exports using Bun's FFI. It provides a single class, Winmm, which lazily binds native symbols on first use. You can optionally preload a subset or all symbols up-front via Preload().

The bindings are strongly typed for a smooth DX in TypeScript.

Features

• Bun-first ergonomics on Windows 10/11.
• Direct FFI to winmm.dll (multimedia audio, MIDI, mixers, timers, joysticks, and MCI).
• In-source docs in structs/Winmm.ts with links to Microsoft Docs.
• Lazy binding on first call; optional eager preload (Winmm.Preload()).
• No wrapper overhead; calls map 1:1 to native APIs.
• Strongly-typed Win32 aliases and a few common flag enums (see types/Winmm.ts).

Requirements

• Bun runtime
• Windows 10 or later

Installation

bun add @bun-win32/winmm

Quick Start

import Winmm from '@bun-win32/winmm';

const tickCount = Winmm.timeGetTime();
const waveOutDeviceCount = Winmm.waveOutGetNumDevs();

console.log({ tickCount, waveOutDeviceCount });

[!NOTE] AI agents: see AI.md for the package binding contract and source-navigation guidance. It explains how to use the package without scanning the entire implementation.

Examples

Run the included examples:

bun run example/winmm.ts
bun run example/synth.ts
bun run example/seq.ts
bun run example/joystick.ts --duration-ms=10000
# or continuous polling
bun run example/joystick.ts --live

Notes

• Either rely on lazy binding or call Winmm.Preload().
• Windows only. Bun runtime required.
• SAL types & naming: nullability is in the type — Optional<T> (formally optional, SAL _*opt_) and Nullable<T> (plain [in]/[out] the docs say can be NULL), the null sentinel derived from T (null for pointers LP*/P*, 0n for handles/by-value addresses); direction is in the parameter name — _out (_Out_), _in_out (_Inout_), _In_ bare. See AI.md and the repo AGENTS.md.