Get tests passing

Author: matthewp

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

@@ -1,3 +1,4 @@
+import fs from 'fs'
 import path from 'path'
 import { tryNodeResolve, InternalResolveOptions } from '../plugins/resolve'
 import {
@@ -93,7 +94,15 @@ export function resolveSSRExternal(
         // entry is not js, cannot externalize
         continue
       }
-      ssrExternals.add(id)
+      if (pkg.type === "module" || entry.endsWith('.mjs')) {
+        ssrExternals.add(id)
+        continue
+      }
+      // check if the entry is cjs
+      const content = fs.readFileSync(entry, 'utf-8')
+      if (/\bmodule\.exports\b|\bexports[.\[]|\brequire\s*\(/.test(content)) {
+        ssrExternals.add(id)
+      }
     }
   }
 

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

@@ -2,7 +2,7 @@ import fs from 'fs'
 import path from 'path'
 import { pathToFileURL } from 'url'
 import { ViteDevServer } from '..'
-import { dynamicImport, cleanUrl, isBuiltin, isObject, resolveFrom, unwrapId } from '../utils'
+import { dynamicImport, cleanUrl, isBuiltin, resolveFrom, unwrapId, usingDynamicImport } from '../utils'
 import { rebindErrorStacktrace, ssrRewriteStacktrace } from './ssrStacktrace'
 import {
   ssrExportAllKey,
@@ -184,29 +184,22 @@ async function nodeImport(
   if (id.startsWith('node:') || isBuiltin(id)) {
     url = id
   } else {
-    url = pathToFileURL(
-      resolve(id, importer, config.root, !!config.resolve.preserveSymlinks)
-    ).toString()
+    url = resolve(id, importer, config.root, !!config.resolve.preserveSymlinks)
+    if (usingDynamicImport) {
+      url = pathToFileURL(url).toString()
+    }
   }
   const mod = await dynamicImport(url)
   return proxyESM(id, mod)
 }
 
 // rollup-style default import interop for cjs
 function proxyESM(id: string, mod: any) {
+  const defaultExport = mod.__esModule ? mod.default : mod
   return new Proxy(mod, {
     get(mod, prop) {
-      if (prop in mod) {
-        return mod[prop]
-      }
-      // commonjs interop: module whose exports are not statically analyzable
-      if (isObject(mod.default) && prop in mod.default) {
-        return mod.default[prop]
-      }
-      // throw an error like ESM import does
-      throw new SyntaxError(
-        `The requested module '${id}' does not provide an export named '${prop.toString()}'`
-      )
+      if (prop === 'default') return defaultExport
+      return mod[prop]
     }
   })
 }

packages/vite/src/node/utils.ts

@@ -569,6 +569,7 @@ export function toUpperCaseDriveLetter(pathName: string): string {
 export const multilineCommentsRE = /\/\*(.|[\r\n])*?\*\//gm
 export const singlelineCommentsRE = /\/\/.*/g
 
+export const usingDynamicImport = typeof jest === 'undefined';
 /**
  * Dynamically import files. It will make sure it's not being compiled away by TS/Rollup.
  *
@@ -578,4 +579,4 @@ export const singlelineCommentsRE = /\/\/.*/g
  *
  * @param file File path to import.
  */
-export const dynamicImport = typeof jest === 'undefined' ? new Function('file', 'return import(file)') : require;
+export const dynamicImport = usingDynamicImport ? new Function('file', 'return import(file)') : require;