feat: support js as ts, ts as esm, etc (#78)

.changeset/curly-falcons-deny.md

@@ -0,0 +1,5 @@
+---
+"synckit": minor
+---
+
+feat: support js as ts, ts as esm, etc

package.json

@@ -41,7 +41,7 @@
     "build": "run-p build:*",
     "build:r": "r -f cjs",
     "build:ts": "tsc -p src",
-    "jest": "node --experimental-vm-modules node_modules/.bin/jest --setupFiles dotenv/config",
+    "jest": "node --experimental-vm-modules node_modules/.bin/jest",
     "lint": "run-p lint:*",
     "lint:es": "eslint . --cache -f friendly --max-warnings 10",
     "lint:tsc": "tsc --noEmit",
@@ -53,10 +53,11 @@
     "typecov": "type-coverage"
   },
   "dependencies": {
+    "@pkgr/utils": "^2.0.3",
     "tslib": "^2.3.1"
   },
   "devDependencies": {
-    "@1stg/lib-config": "^5.3.0",
+    "@1stg/lib-config": "^5.5.0",
     "@changesets/changelog-github": "^0.4.4",
     "@changesets/cli": "^2.22.0",
     "@types/jest": "^27.4.1",
@@ -72,7 +73,7 @@
     "typescript": "^4.6.3"
   },
   "resolutions": {
-    "prettier": "^2.6.1",
+    "prettier": "^2.6.2",
     "tslib": "^2.3.1"
   },
   "commitlint": {
@@ -105,7 +106,7 @@
     ]
   },
   "typeCoverage": {
-    "atLeast": 99.67,
+    "atLeast": 99.73,
     "cache": true,
     "detail": true,
     "ignoreAsAssertion": true,

src/index.ts

@@ -1,4 +1,6 @@
+import { createRequire } from 'module'
 import path from 'path'
+import { pathToFileURL } from 'url'
 import {
   MessageChannel,
   Worker,
@@ -7,6 +9,8 @@ import {
   parentPort,
 } from 'worker_threads'
 
+import { findUp, tryExtensions } from '@pkgr/utils'
+
 import {
   AnyAsyncFn,
   AnyFn,
@@ -18,14 +22,7 @@ import {
 
 export * from './types.js'
 
-const {
-  SYNCKIT_BUFFER_SIZE,
-  SYNCKIT_TIMEOUT,
-  SYNCKIT_TS_ESM,
-  SYNCKIT_EXEC_ARV,
-} = process.env
-
-const TS_USE_ESM = !!SYNCKIT_TS_ESM && ['1', 'true'].includes(SYNCKIT_TS_ESM)
+const { SYNCKIT_BUFFER_SIZE, SYNCKIT_TIMEOUT, SYNCKIT_EXEC_ARV } = process.env
 
 export const DEFAULT_BUFFER_SIZE = SYNCKIT_BUFFER_SIZE
   ? +SYNCKIT_BUFFER_SIZE
@@ -35,6 +32,7 @@ export const DEFAULT_TIMEOUT = SYNCKIT_TIMEOUT ? +SYNCKIT_TIMEOUT : undefined
 
 export const DEFAULT_WORKER_BUFFER_SIZE = DEFAULT_BUFFER_SIZE || 1024
 
+/* istanbul ignore next */
 export const DEFAULT_EXEC_ARGV = SYNCKIT_EXEC_ARV?.split(',') ?? []
 
 const syncFnCache = new Map<string, AnyFn>()
@@ -50,7 +48,7 @@ export interface SynckitOptions {
 // property copying manually.
 export const extractProperties = <T>(object?: T): T | undefined => {
   if (object && typeof object === 'object') {
-    const properties = {} as T
+    const properties = {} as unknown as T
     for (const key in object) {
       properties[key as keyof T] = object[key]
     }
@@ -84,7 +82,7 @@ export function createSyncFn<R, T extends AnyAsyncFn<R>>(
 
   const syncFn = startWorkerThread<R, T>(
     workerPath,
-    typeof bufferSizeOrOptions === 'number'
+    /* istanbul ignore next */ typeof bufferSizeOrOptions === 'number'
       ? { bufferSize: bufferSizeOrOptions, timeout }
       : bufferSizeOrOptions,
   )
@@ -94,8 +92,55 @@ export function createSyncFn<R, T extends AnyAsyncFn<R>>(
   return syncFn
 }
 
-const throwError = (msg: string) => {
-  throw new Error(msg)
+const cjsRequire =
+  typeof require === 'undefined'
+    ? createRequire(import.meta.url)
+    : /* istanbul ignore next */ require
+
+const dataUrl = (code: string) =>
+  new URL(`data:text/javascript,${encodeURIComponent(code)}`)
+
+// eslint-disable-next-line sonarjs/cognitive-complexity
+const setupTsNode = (workerPath: string, execArgv: string[]) => {
+  if (!/[/\\]node_modules[/\\]/.test(workerPath)) {
+    const ext = path.extname(workerPath)
+    // TODO: support `.cts` and `.mts` automatically
+    if (!ext || ext === '.js') {
+      const found = tryExtensions(
+        ext ? workerPath.replace(/\.js$/, '') : workerPath,
+        ['.ts', '.js'],
+      )
+      if (found) {
+        workerPath = found
+      }
+    }
+  }
+
+  const isTs = /\.[cm]?ts$/.test(workerPath)
+
+  // TODO: it does not work for `ts-node` for now
+  let tsUseEsm = workerPath.endsWith('.mts')
+
+  if (isTs) {
+    if (!tsUseEsm) {
+      const pkg = findUp(workerPath)
+      if (pkg) {
+        tsUseEsm =
+          (cjsRequire(pkg) as { type?: 'commonjs' | 'module' }).type ===
+          'module'
+      }
+    }
+    if (tsUseEsm && !execArgv.includes('--loader')) {
+      execArgv = ['--loader', 'ts-node/esm', ...execArgv]
+    }
+  }
+
+  return {
+    isTs,
+    tsUseEsm,
+    workerPath,
+    execArgv,
+  }
 }
 
 function startWorkerThread<R, T extends AnyAsyncFn<R>>(
@@ -108,21 +153,24 @@ function startWorkerThread<R, T extends AnyAsyncFn<R>>(
 ) {
   const { port1: mainPort, port2: workerPort } = new MessageChannel()
 
-  const isTs = workerPath.endsWith('.ts')
+  const {
+    isTs,
+    tsUseEsm,
+    workerPath: finalWorkerPath,
+    execArgv: finalExecArgv,
+  } = setupTsNode(workerPath, execArgv)
 
   const worker = new Worker(
     isTs
-      ? TS_USE_ESM
-        ? throwError(
-            'Native esm in `.ts` file is not supported yet, please use `.cjs` instead',
-          )
-        : `require('ts-node/register');require('${workerPath}')`
-      : workerPath,
+      ? tsUseEsm
+        ? dataUrl(`import '${String(pathToFileURL(finalWorkerPath))}'`)
+        : `require('ts-node/register');require('${finalWorkerPath}')`
+      : finalWorkerPath,
     {
-      eval: isTs,
+      eval: isTs && !tsUseEsm,
       workerData: { workerPort },
       transferList: [workerPort],
-      execArgv,
+      execArgv: finalExecArgv,
     },
   )
 
@@ -158,7 +206,7 @@ function startWorkerThread<R, T extends AnyAsyncFn<R>>(
     }
 
     if (error) {
-      throw Object.assign(error, properties)
+      throw Object.assign(error as object, properties)
     }
 
     return result!

test/cjs/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "cjs-test"
+}

test/cjs/worker-cjs.ts

@@ -0,0 +1,9 @@
+// we're not using `synckit` here because jest can not handle cjs+mjs dual package correctly
+const { runAsWorker } =
+  // eslint-disable-next-line @typescript-eslint/no-require-imports, @typescript-eslint/no-var-requires
+  require('../../lib/index.cjs') as typeof import('synckit')
+
+runAsWorker(
+  <T>(result: T, timeout?: number) =>
+    new Promise<T>(resolve => setTimeout(() => resolve(result), timeout)),
+)

test/esm/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "esm-test",
+  "type": "module"
+}

test/fn.spec.ts

@@ -1,4 +1,6 @@
 import { createRequire } from 'module'
+import path from 'path'
+import { fileURLToPath } from 'url'
 
 import { jest } from '@jest/globals'
 
@@ -11,17 +13,51 @@ beforeEach(() => {
 
   delete process.env.SYNCKIT_BUFFER_SIZE
   delete process.env.SYNCKIT_TIMEOUT
-
-  process.env.SYNCKIT_TS_ESM = '1'
 })
 
 const cjsRequire = createRequire(import.meta.url)
 
-const workerEsmTsPath = cjsRequire.resolve('./worker-esm.ts')
+const _dirname =
+  typeof __dirname === 'undefined'
+    ? path.dirname(fileURLToPath(import.meta.url))
+    : __dirname
+
+const workerCjsTsPath = cjsRequire.resolve('./cjs/worker-cjs.ts')
+const workerEsmTsPath = cjsRequire.resolve('./esm/worker-esm.ts')
+const workerNoExtAsJsPath = path.resolve(_dirname, './worker-js')
+const workerJsAsTsPath = path.resolve(_dirname, './worker.js')
 const workerCjsPath = cjsRequire.resolve('./worker.cjs')
 const workerMjsPath = cjsRequire.resolve('./worker.mjs')
 const workerErrorPath = cjsRequire.resolve('./worker-error.cjs')
 
+test('ts as cjs', () => {
+  const syncFn = createSyncFn<AsyncWorkerFn>(workerCjsTsPath)
+  expect(syncFn(1)).toBe(1)
+  expect(syncFn(2)).toBe(2)
+  expect(syncFn(5)).toBe(5)
+})
+
+test('ts as esm', () => {
+  const syncFn = createSyncFn<AsyncWorkerFn>(workerEsmTsPath)
+  expect(syncFn(1)).toBe(1)
+  expect(syncFn(2)).toBe(2)
+  expect(syncFn(5)).toBe(5)
+})
+
+test('no ext as js (as esm)', () => {
+  const syncFn = createSyncFn<AsyncWorkerFn>(workerNoExtAsJsPath)
+  expect(syncFn(1)).toBe(1)
+  expect(syncFn(2)).toBe(2)
+  expect(syncFn(5)).toBe(5)
+})
+
+test('js as ts (as esm)', () => {
+  const syncFn = createSyncFn<AsyncWorkerFn>(workerJsAsTsPath)
+  expect(syncFn(1)).toBe(1)
+  expect(syncFn(2)).toBe(2)
+  expect(syncFn(5)).toBe(5)
+})
+
 test('createSyncFn', () => {
   expect(() => createSyncFn('./fake')).toThrow('`workerPath` must be absolute')
   expect(() => createSyncFn(cjsRequire.resolve('eslint'))).not.toThrow()
@@ -30,10 +66,6 @@ test('createSyncFn', () => {
   const syncFn2 = createSyncFn<AsyncWorkerFn>(workerCjsPath)
   const syncFn3 = createSyncFn<AsyncWorkerFn>(workerMjsPath)
 
-  expect(() => createSyncFn(workerEsmTsPath)).toThrow(
-    'Native esm in `.ts` file is not supported yet, please use `.cjs` instead',
-  )
-
   const errSyncFn = createSyncFn<() => Promise<void>>(workerErrorPath)
 
   expect(syncFn1).toBe(syncFn2)
@@ -58,7 +90,6 @@ test('createSyncFn', () => {
 test('timeout', async () => {
   process.env.SYNCKIT_BUFFER_SIZE = '0'
   process.env.SYNCKIT_TIMEOUT = '1'
-  process.env.SYNCKIT_TS_ESM = '0'
 
   const { createSyncFn } = await import('synckit')
   const syncFn = createSyncFn<AsyncWorkerFn>(workerCjsPath)

test/worker-error.cjs

@@ -1,3 +1,3 @@
-const { runAsWorker } = require('synckit')
+const { runAsWorker } = require('../lib/index.cjs')
 
 runAsWorker(() => Promise.reject(new Error('Worker Error')))

test/worker-js.js

@@ -0,0 +1,6 @@
+import { runAsWorker } from 'synckit'
+
+runAsWorker(
+  (result, timeout) =>
+    new Promise(resolve => setTimeout(() => resolve(result), timeout)),
+)

test/worker.cjs

@@ -1,3 +1,4 @@
+// we're not using `synckit` here because jest can not handle cjs+mjs dual package correctly
 const { runAsWorker } = require('../lib/index.cjs')
 
 runAsWorker(

test/worker.mjs

@@ -1,4 +1,4 @@
-import { runAsWorker } from '../lib/index.js'
+import { runAsWorker } from 'synckit'
 
 runAsWorker(
   (result, timeout) =>

test/worker.ts

@@ -0,0 +1,6 @@
+import { runAsWorker } from 'synckit'
+
+runAsWorker(
+  (result: number, timeout: number) =>
+    new Promise<number>(resolve => setTimeout(() => resolve(result), timeout)),
+)