@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 is separate from @swifttui/web, the browser runtime. Thus, runtime imports do not include Swift processes, Node filesystem APIs, or wasm packaging helpers.

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

Installation

Install the ESM package from npm. The package includes 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 contains compiled JavaScript in dist/. The binary runs on Node (#!/usr/bin/env node). You do not need Bun or a TypeScript toolchain to use it. To compile a SwiftTUI app to wasm, install Swift 6.4.x and the swift-6.4.0-RELEASE_wasm SDK.

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-6.4.0-RELEASE_wasm
• Release Swift flags: -Xswiftc -Osize -Xswiftc -Xfrontend -Xswiftc -disable-llvm-merge-functions-pass
• Initial memory: 536870912
• Max memory: 4294967296
• Stack size: 16777216 (16 MiB; the earlier 1 MiB default overflowed the wasm linear-memory stack in deep scenes)

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 is in this package. Use the CLI or API instead of a separate swift build command.

Developing this package

Development happens in the swift-tui-web workspace, not against the published tarball. The workspace commands and build pipeline are documented in the repository's docs/DEVELOPMENT.md and packages/build/AGENTS.md. The published CLI stays available as npx swifttui-web build --app <AppExecutable>.

Full SwiftTUI API reference: https://swifttui.sh/docs/documentation/.

License

MIT; see LICENSE.