ReferenceError if editLink callable calls another function

[lukasberbuer]

Describe the bug

I want to use a function within the editLink pattern callable. This results in a ReferenceError:

A `ReferenceError`: getEditLinkPattern is not defined at eval (eval at deserializeFunctions (@siteData:1:228), <anonymous>:4:9)

Reproduction

function getEditLinkPattern(payload: PageData) {
  return "https://github.com/vuejs/vitepress/edit/main/docs/:path";
}

export default {
  themeConfig: {
    editLink: {
      pattern: (payload) => {
        return getEditLinkPattern(payload);
      },
      text: 'Edit this page on GitHub'
    }
  }
}

Expected behavior

The callable in editLink.pattern should be able to reference other functions.

System Info

System:
    OS: Windows 11 10.0.26100
    CPU: (16) x64 AMD Ryzen 7 PRO 7840U w/ Radeon 780M Graphics  
    Memory: 15.65 GB / 30.67 GB
  Binaries:
    Node: 22.14.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.9.2 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (131.0.2903.99)
    Internet Explorer: 11.0.26100.1882
  npmPackages:
    vitepress: ^1.6.3 => 1.6.3

Additional context

No response

Validations

• Check if you're on the latest VitePress version.
• Follow our Code of Conduct
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[brc-dd]

Only "pure" functions are supported - they shouldn't reference any variable outside their scope.

vitepress/docs/en/reference/default-theme-edit-link.md

Line 19 in e06b83e

You can also put a pure function that accepts [`PageData`](./runtime-api#usedata) as the argument and returns the URL string.

vitepress/docs/en/reference/default-theme-edit-link.md

Line 37 in e06b83e

It should not have side-effects nor access anything outside of its scope since it will be serialized and executed in the browser.