macos-nowplaying-bridge

Features

• Control Center ownership — claims the Now Playing slot via a silent audio session, so your app's track info appears in Control Center regardless of what other apps are doing.
• Media-button events — play, pause, toggle, next, and previous button presses from Control Center (or media keys) are forwarded back to Node as typed events.
• Rich metadata — push title, artist, album, artwork URL, duration, elapsed time, playback rate, and play/pause state; Control Center reflects changes immediately.
• Zero npm dependencies — ships a Swift source file compiled lazily on first call with swiftc and wrapped in a minimal .app bundle (required by macOS for Now Playing access).
• No prebuilt binaries — on-demand compilation means no architecture-specific blobs and no native binding steps; the binary is cached in $TMPDIR for subsequent runs.
• macOS only, deliberately — the "os": ["darwin"] guard in package.json prevents accidental installation on unsupported platforms.

Install

npm install @kud/macos-nowplaying-bridge

Requires macOS and Node.js ≥ 20. swiftc must be available (ships with Xcode Command Line Tools).

Usage

import { createNowPlayingBridge } from "@kud/macos-nowplaying-bridge"

const bridge = await createNowPlayingBridge()

// Push track metadata to Control Center
bridge.update({
  title: "Intro",
  artist: "The xx",
  album: "xx",
  duration: 126,
  elapsed: 30,
  state: "playing",
})

// React to Control Center / media-key events
bridge.on("next", () => playNextTrack())
bridge.on("previous", () => playPreviousTrack())
bridge.on("toggle", () => togglePlayback())

// Tear down the co-process when done
bridge.stop()

API

createNowPlayingBridge(): Promise<NowPlayingBridge>

Compiles and spawns the Swift co-process on first call (subsequent calls reuse the cached binary). Throws on non-macOS platforms.

bridge.update(info: NowPlayingInfo): void

Pushes a metadata update. All fields except title are optional.

bridge.on(event: RemoteEvent, handler: () => void): void

Registers a handler for a media-button event. Multiple handlers per event are supported.

RemoteEvent values: "play" · "pause" · "toggle" · "next" · "previous"

bridge.stop(): void

Kills the Swift co-process and releases the Now Playing slot.

Development

git clone https://github.com/kud/macos-nowplaying-bridge.git
cd macos-nowplaying-bridge
npm install
npm run dev