CodeSampleX

Sample

@emnapi/wasi-threads 1.2.2

Verified sample for npm @emnapi/wasi-threads 1.2.2. The contract ran on node 22 · linux debian/x64 · docker and passed: isSharedArrayBuffer identifies…

sha256:0058c6d5052ca9b8155b5813c220b2704b65217dda70b4d56b013ccb234e3a6a

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment linux 24 · ubuntu · glibc 2.39 x64 npm

Verification-run environments

Environment Contract Stages Run
node 22 · linux debian/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22@sha256:8a34c4ab3ea2…
2026-09-19

Case

HOW
Goal
verify pkg:npm/%40emnapi/wasi-threads@1.2.2
Packages
Created
2026-09-18T20:32:22Z

Contract

  1. isSharedArrayBuffer identifies SharedArrayBuffer instances and rejects other types
  2. isTrapError detects WebAssembly.RuntimeError instances and rejects standard Errors
  3. createInstanceProxy wraps a WebAssembly instance and preserves exports
  4. WASIThreads initializes main thread configuration and provides wasi thread-spawn import
  5. WASIThreads enforces postMessage requirement in child thread configuration
  6. ThreadMessageHandler validates postMessage handler and exposes message handling methods
  7. ThreadManager initializes worker pool and tracks worker identifiers

Files

  • PROMPT.md
  • csx.json
  • index.mjs
  • package-lock.json
  • package.json
  • spec.json
  • test/contract.mjs

Download the source artifact (tar.gz)

Source

PROMPT.md
Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/%40emnapi/wasi-threads@1.2.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40emnapi/wasi-threads@1.2.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.
csx.json
{"case":{"caseId":"case:sha256:b1448bb1293d89be5a357297d80d0d72b737386813f7a25771f6398e6772bde0","contract":["isSharedArrayBuffer identifies SharedArrayBuffer instances and rejects other types","isTrapError detects WebAssembly.RuntimeError instances and rejects standard Errors","createInstanceProxy wraps a WebAssembly instance and preserves exports","WASIThreads initializes main thread configuration and provides wasi thread-spawn import","WASIThreads enforces postMessage requirement in child thread configuration","ThreadMessageHandler validates postMessage handler and exposes message handling methods","ThreadManager initializes worker pool and tracks worker identifiers"],"goal":"verify pkg:npm/%40emnapi/wasi-threads@1.2.2","kind":"HOW","packages":["pkg:npm/%40emnapi/wasi-threads@1.2.2"],"schemaVersion":1},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40emnapi/wasi-threads@1.2.2"],"schemaVersion":1,"subject":"pkg:npm/%40emnapi/wasi-threads@1.2.2","verifierAdapter":"node-typescript@1"}
index.mjs
import {
  WASIThreads,
  ThreadManager,
  ThreadMessageHandler,
  createInstanceProxy,
  isSharedArrayBuffer,
  isTrapError
} from '@emnapi/wasi-threads';

/**
 * Creates a WASIThreads manager configured for the given WASI instance.
 *
 * @param {object} wasi - WASI instance conforming to WASIInstance interface.
 * @param {Function} onCreateWorker - Worker factory callback.
 * @param {object} [options] - Additional configuration options.
 * @returns {WASIThreads} Initialized WASIThreads instance.
 */
export function createWASIThreads(wasi, onCreateWorker, options = {}) {
  return new WASIThreads({
    wasi,
    onCreateWorker,
    ...options
  });
}

/**
 * Checks whether a given buffer is a SharedArrayBuffer.
 *
 * @param {*} value - The value to test.
 * @returns {boolean} True if the value is a SharedArrayBuffer.
 */
export function checkSharedArrayBuffer(value) {
  return isSharedArrayBuffer(value);
}

/**
 * Checks whether an error is a WebAssembly trap runtime error.
 *
 * @param {Error} error - The error to inspect.
 * @returns {boolean} True if the error is a WebAssembly.RuntimeError.
 */
export function checkTrapError(error) {
  return isTrapError(error);
}

export {
  WASIThreads,
  ThreadManager,
  ThreadMessageHandler,
  createInstanceProxy,
  isSharedArrayBuffer,
  isTrapError
};
package-lock.json
{
  "name": "sample-wasi-threads",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-wasi-threads",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@emnapi/wasi-threads": "1.2.2"
      }
    },
    "node_modules/@emnapi/wasi-threads": {
      "version": "1.2.2",
      "resolved": "https://registry.npmjs.org/@emnapi/wasi-threads/-/wasi-threads-1.2.2.tgz",
      "integrity": "sha512-c95qOXkHdydNKhscBTebqEC1CVAZpyqOfVfBzQ1qgzyl3gfeldUjIggDbIZgDKsHLgnsM+igH7TJ/eAasaVuMA==",
      "license": "MIT",
      "dependencies": {
        "tslib": "^2.4.0"
      }
    },
    "node_modules/tslib": {
      "version": "2.8.1",
      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.8.1.tgz",
      "integrity": "sha512-oJFu94HQb+KVduSUQL7wnpmqnfmLsOA/nAh6b6EH0wCEoK0/mPeXU6c3wKDV83MkOuHPRHtSXKKU99IBazS/2w==",
      "license": "0BSD"
    }
  }
}
package.json
{
  "name": "sample-wasi-threads",
  "version": "1.0.0",
  "type": "module",
  "main": "index.mjs",
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@emnapi/wasi-threads": "1.2.2"
  }
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40emnapi/wasi-threads@1.2.2",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40emnapi/wasi-threads@1.2.2"
  ]
}
test/contract.mjs
import assert from 'node:assert/strict';
import {
  WASIThreads,
  ThreadManager,
  ThreadMessageHandler,
  createInstanceProxy,
  isSharedArrayBuffer,
  isTrapError,
  createWASIThreads,
  checkSharedArrayBuffer,
  checkTrapError
} from '../index.mjs';

// 1. isSharedArrayBuffer identifies SharedArrayBuffer instances and rejects other types
assert.equal(isSharedArrayBuffer(new SharedArrayBuffer(16)), true);
assert.equal(isSharedArrayBuffer(new ArrayBuffer(16)), false);
assert.equal(isSharedArrayBuffer(null), false);
assert.equal(isSharedArrayBuffer({}), false);
assert.equal(isSharedArrayBuffer('string'), false);
assert.equal(checkSharedArrayBuffer(new SharedArrayBuffer(8)), true);

// 2. isTrapError detects WebAssembly.RuntimeError instances and rejects standard Errors
assert.equal(isTrapError(new WebAssembly.RuntimeError('unreachable')), true);
assert.equal(isTrapError(new Error('general error')), false);
assert.equal(isTrapError(new TypeError('type error')), false);
assert.equal(checkTrapError(new WebAssembly.RuntimeError('trap')), true);

// 3. createInstanceProxy wraps a WebAssembly instance and preserves exports
const wasmBytes = new Uint8Array([0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00]);
const wasmModule = new WebAssembly.Module(wasmBytes);
const wasmInstance = new WebAssembly.Instance(wasmModule);
const proxied = createInstanceProxy(wasmInstance);
assert.ok(typeof proxied === 'object' && proxied !== null);

// 4. WASIThreads initializes main thread configuration and provides wasi thread-spawn import
const mockWasi = { wasiImport: {}, initialize: () => {}, start: () => 0 };
const wtInstance = createWASIThreads(mockWasi, () => ({}));
assert.equal(wtInstance.childThread, false);
assert.ok(wtInstance.PThread instanceof ThreadManager);
const imports = wtInstance.getImportObject();
assert.equal(typeof imports.wasi['thread-spawn'], 'function');

// 5. WASIThreads enforces postMessage requirement in child thread configuration
assert.throws(
  () => new WASIThreads({ wasi: mockWasi, childThread: true }),
  {
    name: 'TypeError',
    message: 'options.postMessage is not a function'
  }
);
const childWt = new WASIThreads({ wasi: mockWasi, childThread: true, postMessage: () => {} });
assert.equal(childWt.childThread, true);
assert.equal(childWt.PThread, undefined);

// 6. ThreadMessageHandler validates postMessage handler and exposes message handling methods
assert.throws(
  () => new ThreadMessageHandler(),
  {
    name: 'TypeError',
    message: 'options.postMessage is not a function'
  }
);
const handler = new ThreadMessageHandler({ postMessage: () => {} });
assert.equal(typeof handler.handle, 'function');
assert.equal(typeof handler.instantiate, 'function');

// 7. ThreadManager initializes worker pool and tracks worker identifiers
const tm = new ThreadManager({ onCreateWorker: () => ({}) });
assert.deepEqual(tm.unusedWorkers, []);
assert.deepEqual(Object.keys(tm.pthreads), []);
assert.equal(typeof tm.nextWorkerID, 'number');

console.log('All @emnapi/wasi-threads contract assertions passed.');

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