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WavedashDocs

Swift

Compile Swift games to WebAssembly with the Swift WebAssembly SDK and JavaScriptKit.

View example project on GitHub Playtest the example project

Swift compiles to WebAssembly via the official Swift WebAssembly SDK, and JavaScriptKit gives you typed access to browser globals. Any Swift program that can drive a <canvas> through JavaScriptKit runs on Wavedash.

Toolchain

Apple's bundled toolchain doesn't ship a wasm-capable clang, so install a standalone Swift 6.3+ toolchain from swift.org. swiftly is the easiest path:

swiftly install 6.3.0

Then install the Swift WebAssembly SDK once:

swift sdk install https://download.swift.org/swift-6.3-release/wasm-sdk/swift-6.3-RELEASE/swift-6.3-RELEASE_wasm.artifactbundle.tar.gz \
  --checksum 9fa4016ee632c7e9e906608ec3b55cf13dfc4dff44e47574c5af58064dc33fd9

Build for web

In your Package.swift, add JavaScriptKit and its PackageToJS plugin. Build with:

swift package --swift-sdk swift-6.3-RELEASE_wasm js -c release
cp -R .build/plugins/PackageToJS/outputs/Package/. dist/
cp Public/index.html dist/

The PackageToJS plugin emits the WASM binary plus a loader in .build/plugins/PackageToJS/outputs/Package/. Point upload_dir at the dist/ folder you assemble.

SDK integration

Wavedash injects window.Wavedash before your wasm loads. Progress reporting happens in two phases:

  1. JS loader (index.js) — stream Pong.wasm byte-by-byte, reporting 0 → 0.95 as bytes arrive.
  2. Swift (main.swift) — call updateLoadProgressZeroToOne(1.0) then init() once the game is ready.

In your index.js entrypoint (generated by PackageToJS, then customized):

const sdk = await window.Wavedash;
sdk.updateLoadProgressZeroToOne(0);

const response = await fetch(new URL("Pong.wasm", import.meta.url));
const total = +response.headers.get("Content-Length") || 0;
let bytes;
if (!total || !response.body) {
  bytes = new Uint8Array(await response.arrayBuffer());
} else {
  const reader = response.body.getReader();
  const chunks = [];
  let received = 0;
  while (true) {
    const { done, value } = await reader.read();
    if (done) break;
    chunks.push(value);
    received += value.length;
    sdk.updateLoadProgressZeroToOne((received / total) * 0.95);
  }
  bytes = new Uint8Array(received);
  let pos = 0;
  for (const c of chunks) { bytes.set(c, pos); pos += c.length; }
}
sdk.updateLoadProgressZeroToOne(0.95);
// then instantiate and run as normal

In your Swift entry point, once the game is ready to play:

import JavaScriptKit

let window = JSObject.global

// Set up canvas, input, game loop with requestAnimationFrame...

if let sdk = window.Wavedash.object {
  _ = sdk.updateLoadProgressZeroToOne!(1.0)

  let opts = JSObject.global.Object.function!.new()
  opts.debug = .boolean(true)
  _ = sdk.`init`!(opts)
}

Calling async SDK methods (leaderboards, UGC, etc.) works through JavaScriptKit's JSPromise — see the SDK setup and Functions reference pages for the full API.

wavedash.toml

game_id = "YOUR_GAME_ID_HERE"
upload_dir = "./dist"
entrypoint = "index.html"

The example repo commits a prebuilt dist/ so you can run wavedash dev without a Swift wasm toolchain. Regenerate it by re-running the swift package ... js -c release command whenever you change Swift sources.