[vite.config.ts - debugging] unable to debug vite config and custom plugins code (VSCode/typescript)

[igrdi]

Describe the bug

I am doing: developing a custom vite plugin and need to debug it in VSCode. For that I've created a project via create vite@latest and vanilla-ts template. Added a vite.config.ts file with a minimal plugin code.

What I expect is: The breakpoints in vite.config.ts are being hit

What actually happening is: The breakpoints are not being hit

I believe the problem is here: (isESM code block)

vite/packages/vite/src/node/config.ts

Line 1898 in a0ed405

async function loadConfigFromBundledFile(

because when I removed "type": "module" from package.json, the breakpoints are being hit. But then the CJS deprecated warning appears in the console.

Reproduction

https://github.com/igrdi/vitejs-vite-vite_config_ts-debug

https://stackblitz.com/~/github.com/igrdi/vitejs-vite-vite_config_ts-debug

Steps to reproduce

1. Create a project vanilla-ts template (for simplicity. Or any other TS template):

npm create vite@latest my-app -- --template vanilla-ts

2. Add vite.config.ts file with the content:

import { defineConfig } from "vite";
export default defineConfig({
  plugins: [
    {
      name: "vite:custom-plugin",
      transformIndexHtml: {
        order: "pre",
        async handler(code) {
          console.log(code);                  // <- set a breakpoint here
        },
      },
    },
  ],
});

3. Open JavaScript Debug Terminal in VSCode and run build command:

npm run build

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (12) x64 Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
    Memory: 18.09 GB / 31.88 GB
  Binaries:
    Node: 22.11.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.9.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (127.0.2651.74)
    Internet Explorer: 11.0.19041.4355
  npmPackages:
    vite: ^6.0.5 => 6.0.10

Used Package Manager

npm

Logs

No response

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• The provided reproduction is a minimal reproducible example of the bug.