Proposal: Allow NextResponse instance to perform redirect() and rewrite() operations

[mattiamalonni]

Goals

1. Improve middleware developer experience by allowing mutation of NextResponse instances (e.g., redirecting) without needing to re-instantiate a new response object.
2. Enable cleaner, more readable middleware logic that avoids unnecessary reassignment of the response variable.
3. Allow use cases like conditional redirects or side effects (e.g., deleting sessions, setting headers/cookies) to be expressed more fluently.

Non-Goals

1. This feature does not aim to replace or modify how NextResponse.redirect() or .rewrite() currently work as static methods.
2. Does not attempt to add new functionality to middleware itself (e.g., new routing logic or new methods for request inspection).
3. Does not aim to change cookie or header APIs; just to make response object mutation more ergonomic.

Background

In current middleware implementations, every time a redirect or rewrite is required, developers must create a new instance of NextResponse using static methods like NextResponse.redirect(...). This leads to a pattern where the response variable must be reassigned multiple times, making the code less readable and harder to manage when handling side effects or cleanup (e.g., clearing cookies or sessions) before returning.

For example:

export default async function middleware(nextRequest: NextRequest) {
  const response = NextResponse.next();

  const user = await getCurrentUser();

  if (!user) {
    const newResponse = NextResponse.redirect(new URL('/login', nextRequest.url));
    newResponse.cookies.delete("session")
    return newResponse;
  }

  return response;
}

This kind of reassignment breaks the flow and can introduce bugs or inconsistencies, especially when side effects rely on a shared response instance. No current workaround exists to fluently mutate the same response object.

Proposal

Add instance methods to NextResponse to support redirecting, rewriting, and other mutations fluently. For example:

export default async function middleware(nextRequest: NextRequest) {
  const response = NextResponse.next();

  const user = await getCurrentUser();

  if (!user) {
    response.cookies.delete("session")
    return response.redirect(new URL('/login', nextRequest.url));
  }

  return response;
}