Can't load the middleware.

MiddlewareCantBeLoaded: An unknown error was thrown while loading your middleware.

What went wrong?

Section titled What went wrong?

Thrown in development mode when middleware throws an error while attempting to loading it.

For example:

import {defineMiddleware} from "astro:middleware";
throw new Error("Error thrown while loading the middleware.")
export const onRequest = defineMiddleware(() => {
  return "string"
});