$ show Julusian/node-elgato-stream-deck
This is a multi-platform TypeScript library for programmatically controlling Elgato Stream Deck devices and the Corsair Galleon K100 keyboard. It provides a unified API over three distinct transport layers: USB HID via `node-hid` (Node.js), WebHID (browser), and TCP/IP (network-connected devices like the Stream Deck Studio and Network Dock). The architecture decouples hardware-specific details behind a service-oriented core: `PropertiesService`, `InputService`, `ButtonsLcdDisplayService`, `LcdSegmentDisplayService`, and `EncoderLedService` are injected into a `StreamDeckBase` class, allowing support for 15+ models (Original, Mini, XL, Plus, Plus XL, Neo, Pedal, Studio, etc.) with minimal duplication. Image processing is modular, with pluggable encoders (JPEG, bitmap) and header generators for different firmware generations. The `PreparedBuffer` pattern enables pre-computing and caching of image writes. The codebase is well-structured as a monorepo with separate packages for core logic, Node.js transport, WebHID transport, TCP transport, and a browser demo. Unit tests use Jest with snapshot testing for HID report payloads. The library is actively maintained, with recent commits, CI pipelines, and automated release-please workflows.
The LLM identified 3 files worth highlighting for reuse:
Implements `PreparedBuffer`, a reusable class that pre-encodes image data into the device's wire format. Once prepared, the buffer can be saved to disk or memory and re-sent without re-encoding. This pattern is useful for any HID device with expensive image compression (e.g., JPEG), and is entirely self-contained with no internal dependencies beyond TypeScript types.
Defines the `ButtonsLcdDisplayService` interface, which abstracts how a device renders LCD button images. The interface requires a single method `setButtonImage` with type-safe parameters for buffer, size, and key index. This is a clean, reusable abstraction that could be adapted to any multi-button grid display, and demonstrates the project's service-oriented architecture.
Provides a JPEG encoder with automatic fallback: attempts `@julusian/jpeg-turbo` for performance, falls back to `jpeg-js` if native bindings are unavailable. The encoder exposes a single `encodeJpeg` function that accepts raw RGBA data and returns a `Uint8Array`. This is a self-contained utility solving the common need for fast JPEG encoding in Node.js with graceful degradation.