feat: support serialization option for child_process runtime

README.md

@@ -181,6 +181,7 @@ We have a similar API to Piscina, so for more information, you can read Piscina'
   - `worker_threads`: Runs workers in [`node:worker_threads`](https://nodejs.org/api/worker_threads.html). For `main thread <-> worker thread` communication you can use [`MessagePort`](https://nodejs.org/api/worker_threads.html#class-messageport) in the `pool.run()` method's [`transferList` option](https://nodejs.org/api/worker_threads.html#portpostmessagevalue-transferlist). See [example](#main-thread---worker-thread-communication).
   - `child_process`: Runs workers in [`node:child_process`](https://nodejs.org/api/child_process.html). For `main thread <-> worker process` communication you can use `TinypoolChannel` in the `pool.run()` method's `channel` option. For filtering out the Tinypool's internal messages see `TinypoolWorkerMessage`. See [example](#main-process---worker-process-communication).
 - `teardown`: name of the function in file that should be called before worker is terminated. Must be named exported.
+- `serialization`: Specify the kind of serialization used for the `child_process` runtime. Possible values are `'json'` and `'advanced'`. See Node.js [Advanced serialization](https://nodejs.org/docs/latest/api/child_process.html#advanced-serialization) for more details.
 
 #### Pool methods
 

src/common.ts

@@ -1,4 +1,5 @@
 import type { MessagePort, TransferListItem } from 'node:worker_threads'
+import type { SerializationType } from 'node:child_process'
 
 /** Channel for communicating between main thread and workers */
 export interface TinypoolChannel {
@@ -21,6 +22,7 @@ export interface TinypoolWorker {
     resourceLimits?: any
     workerData: TinypoolData
     trackUnmanagedFds?: boolean
+    serialization?: SerializationType
   }): void
   terminate(): Promise<any>
   postMessage(message: any, transferListItem?: TransferListItem[]): void

src/index.ts

@@ -3,6 +3,7 @@ import {
   type MessagePort,
   receiveMessageOnPort,
 } from 'node:worker_threads'
+import type { SerializationType } from 'node:child_process'
 import { once, EventEmitterAsyncResource } from 'node:events'
 import { AsyncResource } from 'node:async_hooks'
 import { fileURLToPath, URL } from 'node:url'
@@ -153,6 +154,7 @@ interface Options {
   trackUnmanagedFds?: boolean
   isolateWorkers?: boolean
   teardown?: string
+  serialization?: SerializationType
 }
 
 interface FilledOptions extends Options {
@@ -735,6 +737,7 @@ class ThreadPool {
         this.options.workerData,
       ] as TinypoolData,
       trackUnmanagedFds: this.options.trackUnmanagedFds,
+      serialization: this.options.serialization,
     })
 
     const onMessage = (message: ResponseMessage) => {

test/fixtures/child_process-communication.mjs

@@ -1,13 +1,13 @@
-export default async function run() {
+export default async function run(task) {
   let resolve = () => {}
   const promise = new Promise((r) => (resolve = r))
 
   process.send('Child process started')
 
   process.on('message', (message) => {
     process.send({ received: message, response: 'Hello from worker' })
-    resolve()
+    resolve({ received: task, response: 'Hello from worker' })
   })
 
-  await promise
+  return promise
 }

test/runtime.test.ts

@@ -1,7 +1,7 @@
+import EventEmitter from 'node:events'
 import * as path from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { Tinypool } from 'tinypool'
-import EventEmitter from 'node:events'
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 
@@ -199,6 +199,67 @@ describe('child_process', () => {
     })
   })
 
+  test('can send complex messages to port', async () => {
+    const pool = createPool({
+      runtime: 'child_process',
+      filename: path.resolve(
+        __dirname,
+        'fixtures/child_process-communication.mjs'
+      ),
+      serialization: 'advanced',
+    })
+
+    const complexData = {
+      bigint: 123456789123456789n,
+      map: new Map([['hello', 'world']]),
+      set: new Set(['hello', 'world']),
+      error: new Error('message'),
+      regexp: /regexp/,
+    }
+
+    const emitter = new EventEmitter()
+
+    const startup = new Promise<void>((resolve) =>
+      emitter.on(
+        'response',
+        (message) => message === 'Child process started' && resolve()
+      )
+    )
+
+    const runPromise = pool.run(complexData, {
+      channel: {
+        onMessage: (callback) => emitter.on('message', callback),
+        postMessage: (message) => emitter.emit('response', message),
+      },
+    })
+
+    // Wait for the child process to start
+    await startup
+
+    const response = new Promise<any>((resolve) =>
+      emitter.on('response', (message) => resolve(message))
+    )
+
+    // Send message to child process
+    emitter.emit('message', complexData)
+
+    // Wait for task to finish
+    const runResult = await runPromise
+
+    expect(runResult).toMatchObject({
+      received: complexData,
+      response: 'Hello from worker',
+    })
+
+    // Wait for response from child
+    const channelResult = await response
+
+    expect(channelResult).toMatchObject({
+      received: complexData,
+      response: 'Hello from worker',
+    })
+  })
+
   test('channel is closed when isolated', async () => {
     const pool = createPool({
       runtime: 'child_process',