sveltekit-adapter-bare

⚠️ Highly experimental. This adapter is a proof of concept for running a SvelteKit app inside the bare runtime so it can be packaged with bare-build and rendered in a native window via bare-native. Expect rough edges, missing features, and breaking changes.

A SvelteKit adapter that produces a server bundle runnable by bare instead of Node.js. The output is a plain build/ directory you can hand to bare-build to produce a single-file, native-windowed app.

Demo: https://github.com/Drache93/bare-svelte-demo

Install

npm install --save-dev sveltekit-adapter-bare

All bare runtime deps (bare-http1, bare-fs, bare-native, bare-fetch, bare-form-data, paparam, etc.) are pulled in transitively — you don't need to declare them in your own package.json.

Configure

In svelte.config.js, swap out your adapter:

import adapter from 'sveltekit-adapter-bare';

/** @type {import('@sveltejs/kit').Config} */
const config = {
    compilerOptions: {
        // Force runes mode for the project, except for libraries. Can be removed in svelte 6.
        runes: ({ filename }) => (filename.split(/[/\\]/).includes('node_modules') ? undefined : true)
    },
    kit: {
        // adapter-auto only supports some environments, see https://svelte.dev/docs/kit/adapter-auto for a list.
        // If your environment is not supported, or you settled on a specific environment, switch out the adapter.
        // See https://svelte.dev/docs/kit/adapters for more information about adapters.
        adapter: adapter(),
        csrf: { checkOrigin: false }
    }
};

export default config;

Options:

Build

Three steps — SvelteKit produces the bare-compatible server, bare-build links it for a target platform against the bare-native runtime, and bare-build wraps the result into a native app:

# 1. Vite build — the adapter emits ./build
npm run build

# 2. Build the native app for the target host/arch using the bare-native runtime
npx bare-build \
  --out build/darwin-arm64 \
  --host darwin-arm64 \
  --runtime bare-native/runtime \
  build/index.js

Swap --host / --out to target a different platform (linux-x64, android-arm64, etc.).

The emitted entry (build/index.js) is a small paparam CLI that spins up bare-http1, opens a bare-native window, and loads http://localhost:<port>:

./build/<platform>/<name>.app --width 800 --height 600 --inspectable

Flags:

• --host (default 0.0.0.0) — interface to listen on.
• --port (default 0) — TCP port. 0 asks the OS for a free port; the chosen port is logged at startup and handed to the WebView automatically.
• --width, --height — native window size.
• --inspectable — enable the WebView's remote inspector (connect from desktop Chrome via chrome://inspect).

What the adapter does

• Bundles SvelteKit's server with esbuild, aliasing node:* builtins to their bare-* equivalents.
• Patches out SvelteKit's lazy obfuscated_import("node:crypto") fallback — globalThis.crypto is assigned at startup from bare-crypto.
• Stubs node:async_hooks (bare doesn't ship an equivalent; SvelteKit's AsyncLocalStorage usage works against a minimal shim).
• Emits an assets.js module with one static import.meta.asset() call per file in client/ and prerendered/, so bare-module-traverse preserves every static asset when bare-build bundles the app.
• Polyfills Request.prototype.formData() on top of bare-fetch, supporting application/x-www-form-urlencoded and simple multipart/form-data (text fields) so SvelteKit form actions work.

Known limitations

• multipart/form-data file uploads are not implemented (text fields only).
• No HTTPS, no clustering, no compression, no range requests.
• Android not working yet for multi page

License

Apache-2.0