feat: add new ts runner node for Node22+

.changeset/good-walls-brush.md

@@ -0,0 +1,15 @@
+---
+"synckit": minor
+---
+
+feat: add support for `--experimental-strip-types`
+
+Introducing the `node` runner, which will replace `ts-node` as the new default:
+
+- when running on Node 22 with the `--experimental-strip-types`
+  flag enabled via `NODE_OPTIONS` env or cli args
+- or when running on Node 23+ without `--no-experimental-strip-types`
+  flag enabled via `NODE_OPTIONS` env or cli args
+
+An error will be thrown when attempting to run with `node` on unsupported versions (<22).
+On these versions, the default runner remains `ts-node` when available.

.github/workflows/ci.yml

@@ -57,6 +57,5 @@ jobs:
 
       - name: Codecov
         uses: codecov/codecov-action@v5
-        if: ${{ matrix.node == 18 || matrix.node == 18.18 }}
         with:
           token: ${{ secrets.CODECOV_TOKEN }}

README.md

@@ -22,7 +22,8 @@ Perform async work synchronously in Node.js using `worker_threads` with first-cl
   - [Options](#options)
   - [Envs](#envs)
   - [TypeScript](#typescript)
-    - [`ts-node`](#ts-node)
+    - [`node` (Default, Node 23+)](#node-default-node-23)
+    - [`ts-node` (Default)](#ts-node-default)
     - [`esbuild-register`](#esbuild-register)
     - [`esbuild-runner`](#esbuild-runner)
     - [`swc`](#swc)
@@ -53,7 +54,7 @@ import { createSyncFn } from 'synckit'
 
 // the worker path must be absolute
 const syncFn = createSyncFn(require.resolve('./worker'), {
-  tsRunner: 'tsx', // optional, can be `'ts-node' | 'esbuild-register' | 'esbuild-runner' | 'tsx'`
+  tsRunner: 'tsx', // optional, can be `'node' | 'ts-node' | 'esbuild-register' | 'esbuild-runner' | 'tsx'`
 })
 
 // do whatever you want, you will get the result synchronously!
@@ -126,9 +127,17 @@ export interface GlobalShim {
 
 ### TypeScript
 
-#### `ts-node`
+#### `node` (Default, Node 23+)
 
-If you want to use `ts-node` for worker file (a `.ts` file), it is supported out of box!
+On recent Node versions, you may select this runner to execute your worker file (a `.ts` file) in the native runtime.
+
+As of Node v23, this feature is supported out of the box. To enable it in the current LTS, you can pass the [`--experimental-strip-types`](https://nodejs.org/docs/latest-v22.x/api/typescript.html#type-stripping) flag to the process. Visit the [documentation](https://nodejs.org/docs/latest/api/typescript.html#type-stripping) to learn more.
+
+When `synckit` detects the process to be running with this flag, it will execute the worker file with the `node` runner by default.
+
+#### `ts-node` (Default)
+
+Prior to Node v23, you may want to use `ts-node` to execute your worker file (a `.ts` file).
 
 If you want to use a custom tsconfig as project instead of default `tsconfig.json`, use `TS_NODE_PROJECT` env. Please view [ts-node](https://github.com/TypeStrong/ts-node#tsconfig) for more details.
 

src/index.ts

@@ -33,6 +33,8 @@
 export * from './types.js'
 
 export const TsRunner = {
+  // https://nodejs.org/docs/latest/api/typescript.html#type-stripping
+  Node: 'node',
   // https://github.com/TypeStrong/ts-node
   TsNode: 'ts-node',
   // https://github.com/egoist/esbuild-register
@@ -55,7 +57,23 @@
   SYNCKIT_TS_RUNNER,
 } = process.env
 
-const IS_NODE_20 = Number(process.versions.node.split('.')[0]) >= 20
+export const MTS_SUPPORTED_NODE_VERSION = 16
+export const LOADER_SUPPORTED_NODE_VERSION = 20
+export const STRIP_TYPES_DEFAULT_NODE_VERSION = 23
+export const STRIP_TYPES_SUPPORTED_NODE_VERSION = 22
+
+const NODE_VERSION = Number.parseFloat(process.versions.node)
+const STRIP_TYPES_FLAG = '--experimental-strip-types'
+const NO_STRIP_TYPES_FLAG = '--no-experimental-strip-types'
+const IS_TYPE_STRIPPING_ENABLED =
+  (NODE_VERSION >= STRIP_TYPES_DEFAULT_NODE_VERSION &&
+    !(
+      NODE_OPTIONS?.includes(NO_STRIP_TYPES_FLAG) ||
+      process.argv.includes(NO_STRIP_TYPES_FLAG)
+    )) ||
+  (NODE_VERSION >= STRIP_TYPES_SUPPORTED_NODE_VERSION &&
+    (NODE_OPTIONS?.includes(STRIP_TYPES_FLAG) ||
+      process.argv.includes(STRIP_TYPES_FLAG)))
 
 export const DEFAULT_TIMEOUT = SYNCKIT_TIMEOUT ? +SYNCKIT_TIMEOUT : undefined
 
@@ -80,8 +98,6 @@
   },
 ]
 
-export const MTS_SUPPORTED_NODE_VERSION = 16
-
 let syncFnCache: Map<string, AnyFn> | undefined
 
 export interface SynckitOptions {
@@ -205,11 +221,27 @@
       }
     }
 
-    if (tsRunner == null && isPkgAvailable(TsRunner.TsNode)) {
-      tsRunner = TsRunner.TsNode
+    if (tsRunner == null) {
+      if (IS_TYPE_STRIPPING_ENABLED) {
+        tsRunner = TsRunner.Node
+      } else if (isPkgAvailable(TsRunner.TsNode)) {
+        tsRunner = TsRunner.TsNode
+      }
     }
 
     switch (tsRunner) {
+      case TsRunner.Node: {
+        if (NODE_VERSION < STRIP_TYPES_SUPPORTED_NODE_VERSION) {
+          throw new Error(
+            'type stripping is not supported in this node version',
+          )
+        }
+        execArgv =
+          NODE_VERSION >= STRIP_TYPES_DEFAULT_NODE_VERSION
+            ? execArgv.filter(arg => arg !== NO_STRIP_TYPES_FLAG)
+            : [STRIP_TYPES_FLAG, ...execArgv]
+        break
+      }
       case TsRunner.TsNode: {
         if (tsUseEsm) {
           if (!execArgv.includes('--loader')) {
@@ -283,7 +315,7 @@
         // https://github.com/un-ts/synckit/issues/123
         resolvedPnpLoaderPath = pathToFileURL(pnpLoaderPath).toString()
 
-        if (!IS_NODE_20) {
+        if (NODE_VERSION < LOADER_SUPPORTED_NODE_VERSION) {
           execArgv = [
             '--experimental-loader',
             resolvedPnpLoaderPath,
@@ -452,8 +484,7 @@
 
   if (/\.[cm]ts$/.test(finalWorkerPath)) {
     const isTsxSupported =
-      !tsUseEsm ||
-      Number.parseFloat(process.versions.node) >= MTS_SUPPORTED_NODE_VERSION
+      !tsUseEsm || NODE_VERSION >= MTS_SUPPORTED_NODE_VERSION
     /* istanbul ignore if */
     if (!finalTsRunner) {
       throw new Error('No ts runner specified, ts worker path is not supported')
@@ -604,7 +635,7 @@
 
   const { workerPort, sharedBuffer, pnpLoaderPath } = workerData as WorkerData
 
-  if (pnpLoaderPath && IS_NODE_20) {
+  if (pnpLoaderPath && NODE_VERSION >= LOADER_SUPPORTED_NODE_VERSION) {
     module.register(pnpLoaderPath)
   }
 

test/ts-runner.spec.ts

@@ -7,7 +7,12 @@ import { jest } from '@jest/globals'
 import { _dirname, nodeVersion, tsUseEsmSupported } from './helpers.js'
 import type { AsyncWorkerFn } from './types.js'
 
-import { MTS_SUPPORTED_NODE_VERSION, TsRunner } from 'synckit'
+import {
+  MTS_SUPPORTED_NODE_VERSION,
+  STRIP_TYPES_DEFAULT_NODE_VERSION,
+  STRIP_TYPES_SUPPORTED_NODE_VERSION,
+  TsRunner,
+} from 'synckit'
 
 beforeEach(() => {
   jest.resetModules()
@@ -130,6 +135,44 @@ test(TsRunner.TSX, async () => {
   expect(syncFn(5)).toBe(5)
 })
 
+test(TsRunner.Node, async () => {
+  const { createSyncFn } = await import('synckit')
+
+  if (nodeVersion < STRIP_TYPES_SUPPORTED_NODE_VERSION) {
+    // eslint-disable-next-line jest/no-conditional-expect
+    expect(() =>
+      createSyncFn<AsyncWorkerFn>(workerMtsPath, {
+        tsRunner: TsRunner.Node,
+      }),
+    ).toThrow('type stripping is not supported in this node version')
+    return
+  }
+
+  let syncFn = createSyncFn<AsyncWorkerFn>(workerJsPath, {
+    tsRunner:
+      nodeVersion >= STRIP_TYPES_DEFAULT_NODE_VERSION
+        ? undefined
+        : TsRunner.Node,
+  })
+  expect(syncFn(1)).toBe(1)
+  expect(syncFn(2)).toBe(2)
+  expect(syncFn(5)).toBe(5)
+
+  if (!tsUseEsmSupported) {
+    return
+  }
+
+  syncFn = createSyncFn<AsyncWorkerFn>(workerMtsPath, {
+    tsRunner:
+      nodeVersion >= STRIP_TYPES_DEFAULT_NODE_VERSION
+        ? undefined
+        : TsRunner.Node,
+  })
+  expect(syncFn(1)).toBe(1)
+  expect(syncFn(2)).toBe(2)
+  expect(syncFn(5)).toBe(5)
+})
+
 test('unknown ts runner', async () => {
   const { createSyncFn } = await import('synckit')