Does nextjs middleware matcher uses different regex than usual js regex?

Question

I'm trying to implement a middleware for my website using nextauth. I have a matcher exported like this:

export const config = { matcher: ["\/((?!api|_next\/static|_next\/image|favicon\.ico|[^\.]+\..+).*)"] }

I have tested this regex in some online regex tester (like regex101). The purpose of the regex is to ignore all paths which start from api,_next/static etc and ignore the ones which are like media files([^\.]+\..+) . Even though it works in other regex tester it doesn't work in the nextjs.

I have noticed that in nextjs they used . without escaping (in favicon.ico), why?

American black bear · Accepted Answer

The right way: /((?!api|_next/static|_next/image|favicon\.ico|[^\.]+\..+).*)I should escape backslashes.

Does nextjs middleware matcher uses different regex than usual js regex?

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