Getting errors while developing firebase-cloud-messaging app

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#### Observed Results:

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So I'm developing a firebase cloud messaging app and getting some issues.
I solved most of the issues by myself but still unable to find the solutions of some problems.
The problem here is that I'm using SDK V9 and the code in this repo is not using the moduler code.
Instead of it, still the old styled code is being used (compat) one and hence it is creating a lot of problem for new comers.
My code is in below repo:
https://github.com/firebase/quickstart-js
And the first issue which I'm having is:
FirebaseError: Messaging: We are unable to register the default service worker. Failed to register a ServiceWorker for scope ('http://localhost:3000/firebase-cloud-messaging-push-scope') with script ('http://localhost:3000/firebase-messaging-sw.js'): ServiceWorker script evaluation failed (messaging/failed-service-worker-registration).
at registerDefaultSw (registerDefaultSw.ts:43)
at async updateSwReg (updateSwReg.ts:28)
at async getToken$1 (getToken.ts:43)