napi-rs/examples/napi/__tests__/worker.cjs

const { parentPort } = require('worker_threads')

const isWasiTest = !!process.env.WASI_TEST

import('../index.js').then(({ default: native }) => {
  parentPort.on('message', ({ type }) => {
    switch (type) {
      case 'require':
        parentPort.postMessage(
          native.Animal.withKind(native.Kind.Cat).whoami() + native.DEFAULT_COST,
        )
        break
      case 'async:buffer':
        Promise.all(
          Array.from({ length: isWasiTest ? 2 : 100 }).map(() =>
            native.bufferPassThrough(Buffer.from([1, 2, 3])),
          ),
        )
          .then(() => {
            parentPort.postMessage('done')
          })
          .catch((e) => {
            throw e
          })
        break
      case 'async:arraybuffer':
        Promise.all(
          Array.from({ length: isWasiTest ? 2 : 100 }).map(() =>
            native.arrayBufferPassThrough(Uint8Array.from([1, 2, 3])),
          ),
        )
          .then(() => {
            parentPort.postMessage('done')
          })
          .catch((e) => {
            throw e
          })

        break
      case 'constructor':
        let ellie
        for (let i = 0; i <  (isWasiTest ? 10 : 10000); i++) {
          ellie = new native.Animal(native.Kind.Cat, 'Ellie')
        }
        parentPort.postMessage(ellie.name)
        break
      default:
        throw new TypeError(`Unknown message type: ${type}`)
    }
  })
}).catch((e) => {
  console.error(e)
  process.exit(1)
})