fix: pass yarn PnP experimental loader to worker if it exists

.changeset/weak-yaks-remain.md

@@ -0,0 +1,5 @@
+---
+"synckit": patch
+---
+
+fix: pass yarn PnP experimental loader to worker if it exists

src/index.ts

@@ -1,3 +1,4 @@
+import fs from 'node:fs'
 import { createRequire } from 'node:module'
 import path from 'node:path'
 import { pathToFileURL } from 'node:url'
@@ -127,6 +128,14 @@ const cjsRequire =
 const dataUrl = (code: string) =>
   new URL(`data:text/javascript,${encodeURIComponent(code)}`)
 
+export const isFile = (path: string) => {
+  try {
+    return fs.statSync(path).isFile()
+  } catch {
+    return false
+  }
+}
+
 const setupTsRunner = (
   workerPath: string,
   { execArgv, tsRunner }: { execArgv: string[]; tsRunner: TsRunner }, // eslint-disable-next-line sonarjs/cognitive-complexity
@@ -223,6 +232,10 @@ const setupTsRunner = (
       !execArgv.includes(pnpApiPath)
     ) {
       execArgv = ['-r', pnpApiPath, ...execArgv]
+      const pnpLoaderPath = path.resolve(pnpApiPath, '../.pnp.loader.mjs')
+      if (isFile(pnpLoaderPath)) {
+        execArgv = ['--experimental-loader', pnpLoaderPath, ...execArgv]
+      }
     }
   }
 

test/fixtures/yarn-pnp/.yarnrc.yml

@@ -1,3 +1,3 @@
 nodeLinker: pnp
-
+pnpEnableEsmLoader: true
 yarnPath: .yarn/releases/yarn-3.2.2.cjs

test/utils.spec.ts

@@ -0,0 +1,11 @@
+import { fileURLToPath } from 'node:url'
+
+import { _dirname } from './helpers'
+
+import { isFile } from 'synckit'
+
+test('utils', () => {
+  expect(isFile(_dirname)).toBe(false)
+  expect(isFile('non-existed')).toBe(false)
+  expect(isFile(fileURLToPath(import.meta.url))).toBe(true)
+})