@swifttui/build

Build tooling for SwiftTUI browser deployments — compile a SwiftTUI app to wasm32-wasi and capture its scene manifest.

@swifttui/build turns a SwiftTUI app into the two artifacts the browser needs: an app.wasm and a scene-manifest.json. It drives the Swift toolchain, runs a browser WebAssembly.compile validation pass, and packages the result. It intentionally sits outside @swifttui/web (the browser runtime) so runtime imports never pull in Swift process spawning, Node filesystem APIs, or wasm packaging helpers.

• Runtime counterpart: @swifttui/web — mounts the artifacts this package produces.
• Reference template: swift-tui-examples/WebExample
• The framework: SwiftTUI/swift-tui

Installation

Published to npm as an ESM package with a Node CLI and bundled TypeScript declarations:

npm install --save-dev @swifttui/build

This exposes the swifttui-web CLI (npx swifttui-web build --app <Exe>) and a programmatic ESM API. The package ships compiled dist/ JavaScript — the bin runs on plain Node (#!/usr/bin/env node), no Bun or TypeScript toolchain required to consume it. Building a SwiftTUI app to wasm does require a Swift 6.3.x toolchain and the swift-6.3.1-RELEASE_wasm SDK on your machine.

Use

From the command line:

npx swifttui-web build --app <AppExecutable>

Or programmatically:

import { buildSwiftTUIWebApp } from "@swifttui/build";

await buildSwiftTUIWebApp({
  packagePath: ".",
  product: "MyApp",
  outputDirectory: "dist",
});

Toolchain defaults match the repo:

• Swift command: swiftly run swift when swiftly is on PATH, otherwise swift
• SDK: swift-6.3.1-RELEASE_wasm
• Release Swift flags: -Xswiftc -Osize -Xswiftc -Xfrontend -Xswiftc -disable-llvm-merge-functions-pass
• Initial memory: 536870912
• Max memory: 4294967296
• Stack size: 1048576

Callers can override swiftCommand, swiftSDK, configuration, initialMemory, maxMemory, stackSize, extraSwiftcFlags, extraLinkerFlags, and extraSwiftBuildArgs.

The WASI release flags (-Osize plus -disable-llvm-merge-functions-pass) keep the output under the browser WebAssembly API's 1000-parameter limit. The canonical command lives in this package — prefer the CLI/API over a hand-rolled swift build.

Developing this package

Only needed if you are working on @swifttui/build itself. Consuming it from a project needs only npm install --save-dev (above).

Use Bun for the CLI, bundling, and tests, and swiftly Swift 6.3.1 for the wasm build it invokes (not bare swift).

• bun test
• bun run build — compile the publishable package to dist/ with tsdown (ESM .js + .d.ts, plus the swifttui-web bin). Run automatically on publish via prepublishOnly.
• bun run build:manifest -- --app <AppExecutable>
• bun run build:wasm -- --app <AppExecutable>

The full app pipeline (manifest + wasm) is exposed through the CLI:

bun run cli.ts build --app <AppExecutable>    # from source
npx swifttui-web build --app <AppExecutable>  # from the published bin

License

MIT — see LICENSE.