Describe the bug

See reproduction link. The prebundled deps generated locally looks this, resulting in an incorrect accessor pattern for getting the property "default" within the JSON that results in undefined in this case:

We ran into this issue last friday as one of our NPM packages contains an JSON that has "default" as top-level property in the JSON, resulting in null exception during local dev serve.

Reproduction

https://stackblitz.com/edit/vitejs-vite-yx2cumr5?file=src%2Fmain.js,src%2Flib.js&terminal=dev

Steps to reproduce

Open the link and check the console for output. You should see the following somewhere in the console:

System Info

System:
    OS: Windows 11 10.0.26100
    CPU: (22) x64 Intel(R) Core(TM) Ultra 9 185H
    Memory: 37.51 GB / 63.45 GB
  Binaries:
    Node: 24.15.0 - C:\Program Files\nodejs\node.EXE
    npm: 11.12.1 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 148.0.7778.179
    Edge: Chromium (142.0.3595.53)
    Firefox: 151.0 - C:\Program Files\Mozilla Firefox\firefox.exe
  npmPackages:
    vite: ^8.0.12 => 8.0.14

Used Package Manager

npm

Logs

No response

Validations

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