Group client and server exports

[afoures]

The proposal

Group client side only exports in client object and server side only exports in server object.
All exports that will run in both client and server would still be exported like today.

By grouping exports together that only run in one environment, it should be easier to understand what code runs where.

// before
export function headers() {
}

export function loader() {
  // ..
}
export function action() {
  // ..
}
export function clientLoader() {
  // ..
}
export function clientAction() {
  // ..
}

// after
export const server = {
  // middlewares: [], -- in the future
  headers() {
    // ..
  },
  loader() {
    // ..
  },
  action() {
    // ..
  }
}

export const client = {
  // middlewares: [], -- in the future
  loader() {
    // ..
  },
  action() {
    // ..
  }
}

Potential issues

• Code splitting and bundling: because we group loader and action (client and server), code splitting could be harder to do?
• Grouping server only and client only code and keeping all "shared" code (Component, ErrorBoundary, handle, ...) as simple exports could also not make it clearer. Questions like: "but why all of those are not grouped in a shared object?" may happen.