Using build.lib.entry yields error The symbol "__cjs_url__" has already been declared and similar with ES module

[vincesp]

Describe the bug

Defining one or several build.lib.entry entries results in an error during the Vite build if "type" is set to "module" in package.json:

export default defineConfig({
// ...
  preload: {
    plugins: [externalizeDepsPlugin()],
    build: {
      lib: {
        entry: [resolve('src/preload/myindex.js')]
      }
    }
  },
// ...
})

Error:

The symbol "__cjs_url__" has already been declared
8  |  
9  |  // -- CommonJS Shims --
10 |  import __cjs_url__ from 'node:url';
   |         ^
11 |  import __cjs_path__ from 'node:path';
12 |  import __cjs_mod__ from 'node:module';

The symbol "__cjs_path__" has already been declared
9  |  // -- CommonJS Shims --
10 |  import __cjs_url__ from 'node:url';
11 |  import __cjs_path__ from 'node:path';
   |         ^
12 |  import __cjs_mod__ from 'node:module';
13 |  const __filename = __cjs_url__.fileURLToPath(import.meta.url);

The symbol "__cjs_mod__" has already been declared
10 |  import __cjs_url__ from 'node:url';
11 |  import __cjs_path__ from 'node:path';
12 |  import __cjs_mod__ from 'node:module';
   |         ^
13 |  const __filename = __cjs_url__.fileURLToPath(import.meta.url);
14 |  const __dirname = __cjs_path__.dirname(__filename);

The symbol "__filename" has already been declared
14 |  const __dirname = __cjs_path__.dirname(__filename);
15 |  const require = __cjs_mod__.createRequire(import.meta.url);
16 |  const __filename = __cjs_url__.fileURLToPath(import.meta.url);
   |        ^
17 |  const __dirname = __cjs_path__.dirname(__filename);
18 |  __cjs_mod__.createRequire(import.meta.url);

The symbol "__dirname" has already been declared
15 |  const require = __cjs_mod__.createRequire(import.meta.url);
16 |  const __filename = __cjs_url__.fileURLToPath(import.meta.url);
17 |  const __dirname = __cjs_path__.dirname(__filename);
   |        ^
18 |  __cjs_mod__.createRequire(import.meta.url);
19 |  const icon = join(__dirname, "../../resources/icon.png");

✓ built in 55ms
 ERROR  Transform failed with 5 errors:
index.mjs:10:7: ERROR: The symbol "__cjs_url__" has already been declared
index.mjs:11:7: ERROR: The symbol "__cjs_path__" has already been declared
index.mjs:12:7: ERROR: The symbol "__cjs_mod__" has already been declared
index.mjs:16:6: ERROR: The symbol "__filename" has already been declared
index.mjs:17:6: ERROR: The symbol "__dirname" has already been declared

Here is a Codesandbox to reproduce the error.

Electron-Vite Version

2.0.0

Electron Version

28.1.4

Vite Version

5.0.12

Validations

• Follow the Code of Conduct.
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[vincesp]

There is a workaround: we can use build.rollupOptions.input instead:

build: {
  rollupOptions: {
    input: [resolve('src/preload/myindex.js')]
  }
}

This also requires to update the BrowserWindow options in main/index.js and change the file name extension to .mjs:

webPreferences: {
  preload: join(__dirname, '../preload/myindex.mjs'),
  sandbox: false
}

See branch fix/double-symbol

[alex8088]

new ver 2.1.0 is out 🎉.

[vincesp]

I tested it, see branch test/v2.1.0

I noticed the odd behavior that the files under out/preload/ are generated with the .mjs extension, while the files under out/main/ are correctly generated with the .js extension. As the whole package is of `"type": "module"``, the .mjs extension should not be required.

This means that in main.js, I cannot simply reference the preload file with the name they have under src/:

webPreferences: {
  preload: join(__dirname, '../preload/myindex.js'),
  sandbox: false
}

But I have to use a different file name extension, which is not intuitive:

webPreferences: {
  preload: join(__dirname, '../preload/myindex.mjs'),
  sandbox: false
}

Is there a reason for this deviation between src/ and out/?