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sidecar

import { sidecar } from "@tynd/core/client";

Registry of binaries extracted from the TYNDPKG sidecar/* section at startup.

path(name): Promise<string>

Returns the extracted on-disk path of a sidecar. Throws if no sidecar by that name was packed.

const ffmpegPath = await sidecar.path("ffmpeg.exe");

list(): Promise<Array<{ name: string; path: string }>>

Enumerate every registered sidecar with its extracted path.

const all = await sidecar.list();
// [{ name: "ffmpeg.exe", path: "/tmp/tynd-xxxx/sidecar/ffmpeg.exe" }, …]

Declare at build time

tynd.config.ts
sidecars: [
  { name: "ffmpeg.exe", path: "bin/ffmpeg.exe" },
  { name: "yt-dlp",     path: "bin/yt-dlp" },
]
  • name — what your runtime code queries by.
  • path — where the binary lives at build time (relative to project root).

Execute via process.exec

import { sidecar, process } from "@tynd/core/client";
 
const ffmpeg = await sidecar.path("ffmpeg.exe");
const { stdout, code } = await process.exec(ffmpeg, {
  args: ["-i", input, "-c:v", "libx264", output],
});

What happens under the hood

At launch, the Rust host walks TYNDPKG and, for every entry under sidecar/:

  1. Extracts the bytes to <temp_dir>/sidecar/<name>.
  2. On Unix, chmods +755.
  3. Registers the path in a Mutex<HashMap<name, PathBuf>> inside os::sidecar.

sidecar.path(name) looks up the map.

Platform-specific binaries

Cross-compilation isn’t supported. CI matrix pattern — stage the right binary per host before tynd build:

- name: Stage sidecar for this host
  shell: bash
  run: |
    case "${{ matrix.target }}" in
      windows-x64)  curl -L -o bin/ffmpeg.exe https://…/ffmpeg-win-x64.exe ;;
      linux-x64)    curl -L -o bin/ffmpeg https://…/ffmpeg-linux-x64 ;;
      macos-arm64)  curl -L -o bin/ffmpeg https://…/ffmpeg-macos-arm64 ;;
    esac

See the Sidecars guide.

Notes

  • Sidecars are not zstd-compressed in TYNDPKG — they’re already-compressed formats.
  • They inflate your final binary by their uncompressed size.
  • On macOS, a signed outer .app doesn’t extend its signature to extracted sidecars; sign them separately or accept Gatekeeper prompts.
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