@antjs.org/wasm #

Embed the Ant Silver interpreter for sandboxing using WASM. Each Ant instance owns its WebAssembly memory and keeps its own global state.

import { Ant } from '@antjs.org/wasm';

const ant = await Ant.create();
try {
  const result = await ant.eval(`
    Array.from({ length: 5 }, (_, i) => i ** 2)
  `);
  console.log(result); // [0, 1, 4, 9, 16]
} finally {
  ant.dispose();
}

Configure a hard memory ceiling, a guest execution timeout, and synchronous host functions at creation time:

import { Ant } from '@antjs.org/wasm';

const ant = await Ant.create({
  memoryLimit: 64 * 1024 * 1024,
  timeout: 1_000,
  globals: { greet: name => `Hello, ${name}!` }
});

try {
  const value = await ant.eval(`greet("Silver")`);
  console.log(value); // Hello, Silver!
} finally {
  ant.dispose();
}

API #

Ant.create(options?) asynchronously instantiates a fresh engine. The default memory limit is 128 MiB. The minimum is 32 MiB and WebAssembly applies the limit in 64 KiB pages, so memoryLimit must be page-aligned. A timeout of 0 (the default) disables the execution deadline.

ant.eval(source) evaluates source with persistent global state and returns a Promise for its completion value. Call dispose() when explicit resource management syntax is not available. On runtimes that implement explicit resource management, using ant = await Ant.create() disposes automatically.

Numbers (including non-finite values and negative zero), booleans, strings, BigInts, null, undefined, arrays, and enumerable string-keyed object data cross the boundary. Cycles, symbols, and nested functions are rejected. A function supplied directly in globals can be called by guest code, but it must return synchronously. Guest module imports, native APIs, subprocesses, networking, the package manager, and JIT compilation are not part of this interpreter-only build.

Promise reactions and resolved await continuations run at the evaluation checkpoint. Promise objects themselves cannot cross the host boundary, and this package does not provide timers or external asynchronous I/O inside the guest.

The timeout interrupts Silver bytecode execution. It cannot preempt a host callback while that callback is running on the same JavaScript thread. Put an instance in a Web Worker when the embedding must also isolate host callbacks from the page's main thread.

Examples #

The examples gallery covers basic evaluation, host functions, state isolation, a rules-engine pattern, limits, and error handling. In a repository checkout, build once and then run all Node examples:

npm run build
npm run examples

Build #

npm run build

Run npm test for package validation.

The build downloads the host build of wasi-sdk 34, verifies its SHA-256 digest, and compiles a wasm32-wasip1 reactor with Clang and wasm-ld. Set WASI_SDK_PATH to use an existing wasi-sdk 34 installation. Generated build, cache, and package artifacts stay under this package and are ignored by Git.

The published package contains the stripped ant.wasm, the Ant-owned ESM loader, and declarations. It contains no Emscripten loader. The build rejects any unreviewed Wasm import or export; the retained WASI Preview 1 calls are a small libc subset implemented by the loader without filesystem preopens or environment access.

Serve ant.wasm with Content-Type: application/wasm for streaming browser compilation. The loader falls back to buffered compilation when that MIME type is unavailable.