Functions in theme config are always undefined

[Yuhanawa]

problem

index.ts in theme

export default defineTheme({
  schema: z.object({
    customScript: z.function(),
  })
})

astro.config.ts in playground

integrations: [
  theme({
    config: {
      customScript: () => {
        console.log("test");
      },
    },
  }),
],

file in theme

import config from "theme:config";

console.log(config.customScript); // undefined

possible reason

astro-theme-provider/package/src/index.ts

Line 123 in dd63fc8

[`${themeName}:config`]: `export default ${JSON.stringify(userConfig)}`,

using JSON.stringify in this line

possible solution

JSON.stringify(
  Object.fromEntries(
    Object.entries(userConfig).map(([key, value]) => 
      typeof value === 'function' 
        ? [key, value.toString()] 
        : [key, value]
        )
    )
)

[BryceRussell]

This is a limitation of the config option / ATP in general. The value has to be JSON serializable so that the config can be turned into a virtual module and functions cannot be serialized into JSON.

Supporting something like this may be possible using @inox-tools/inline-mod, more details in this issue here: #32