feat(ssr): import.meta.filename/dirname support (#15887)

Author: sapphi-red

packages/vite/src/node/ssr/__tests__/fixtures/modules/import-meta.js

@@ -0,0 +1,2 @@
+export const dirname = import.meta.dirname
+export const filename = import.meta.filename

packages/vite/src/node/ssr/__tests__/ssrLoadModule.spec.ts

@@ -52,3 +52,13 @@ test('error has same instance', async () => {
     expect(e[s]).toBe(true)
   }
 })
+
+test('import.meta.filename/dirname returns same value with Node', async () => {
+  const server = await createDevServer()
+  const moduleRelativePath = '/fixtures/modules/import-meta.js'
+  const filename = path.resolve(root, '.' + moduleRelativePath)
+
+  const viteValue = await server.ssrLoadModule(moduleRelativePath)
+  expect(viteValue.dirname).toBe(path.dirname(filename))
+  expect(viteValue.filename).toBe(filename)
+})

packages/vite/src/node/ssr/ssrModuleLoader.ts

@@ -10,6 +10,7 @@ import { genSourceMapUrl } from '../server/sourcemap'
 import {
   AsyncFunction,
   asyncFunctionDeclarationPaddingLineCount,
+  isWindows,
   unwrapId,
 } from '../../shared/utils'
 import {
@@ -112,7 +113,12 @@ async function instantiateModule(
   // referenced before it's been instantiated.
   mod.ssrModule = ssrModule
 
+  // replace '/' with '\\' on Windows to match Node.js
+  const osNormalizedFilename = isWindows ? path.resolve(mod.file!) : mod.file!
+
   const ssrImportMeta = {
+    dirname: path.dirname(osNormalizedFilename),
+    filename: osNormalizedFilename,
     // The filesystem URL, matching native Node.js modules
     url: pathToFileURL(mod.file!).toString(),
   }