Fetchwrapper usage with sveltekit - problem reproduction

• git clone git@github.com:0gust1/sveltekit-fetchwrapper-repro.git
• cd sveltekit-fetchwrapper-repro
• npm i && npm run dev

Problem description

To facilitate error management and avoid error management boilerplates on fetch requests, we use a small wrapper around the native fetch function.

example code in src/lib/utils/fetchwrapper.ts

This wrapper can take a fetchlib instance parameter, in order to handle the sveltekit's special fetch

However, when using this wrapper in a +page.server.ts file:

• a fetch to an external API works.
• a fetch to an internal endpoint ( /api/example-123 here ) breaks.

Questions:

• is there a way to make this wrapper work with internal endpoints?
• I guess the problem is that Sveltekit captures the request and tries to handle it, but I don't know how to make it work.

When it break, we get the following stacktrace:

TypeError: Failed to parse URL from /api/example-123
at new Request (PROJECT_PATH/node_modules/undici/lib/fetch/request.js:87:15)
at Module.get (PROJECT_PATH/src/lib/utils/fetchWrapper.ts:83:23)
at load (PROJECT_PATH/src/routes/internal-api-load-wrapped/+page.server.ts:5:27)
at Module.load_server_data (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/page/load_data.js:51:41)
at PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/data/index.js:62:13
at async Promise.all (index 1)
at async Module.render_data (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/data/index.js:100:17)
at async resolve (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/respond.js:394:17)
at async Module.respond (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/respond.js:274:20)
at async file://PROJECT_PATH/node_modules/@sveltejs/kit/src/exports/vite/dev/index.js:510:22  {
[cause]: TypeError [ERR_INVALID_URL]: Invalid URL
    at new NodeError (node:internal/errors:393:5)
    at URL.onParseError (node:internal/url:565:9)
    at new URL (node:internal/url:645:5)
    at new Request (PROJECT_PATH/node_modules/undici/lib/fetch/request.js:85:21)
    at Module.get (PROJECT_PATH/src/lib/utils/fetchWrapper.ts:52:21)
    at load (PROJECT_PATH/src/routes/internal-api-load-wrapped/+page.server.ts:8:50)
    at Module.load_server_data (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/page/load_data.js:57:41)
    at eval (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/data/index.js:73:35)
    at async Promise.all (index 1)
    at async Module.render_data (PROJECT_PATH/node_modules/@sveltejs/kit/src/runtime/server/data/index.js:111:17)  {
  input: '/api/example-123',
  code: 'ERR_INVALID_URL'
  }
  }

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