no service-worker.js file after npm run build in react - reactjs

Question

After running npm run dev no service-worker.js file in build folder.
I'm also changed serviceWorker.register() in index.js
I'm also using firebase in this project.
Here is package.json file
{
"name": "movie",
"version": "0.1.0",
"private": true,
"dependencies": {
"#testing-library/jest-dom": "^4.2.4",
"#testing-library/react": "^9.5.0",
"#testing-library/user-event": "^7.2.1",
"axios": "^0.20.0",
"email-verifier": "^0.4.1",
"firebase": "^7.24.0",
"history": "^5.0.0",
"react": "^16.13.1",
"react-dom": "^16.13.1",
"react-lottie": "^1.2.3",
"react-router-dom": "^5.2.0",
"react-scripts": "^4.0.0"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},
"eslintConfig": {
"extends": "react-app"
},
"browserslist": {
"production": [
">0.2%",
"not dead",
"not op_mini all"
],
"development": [
"last 1 chrome version",
"last 1 firefox version",
"last 1 safari version"
]
},
"devDependencies": {
"#types/react-router-dom": "^5.1.6"
}
}
After deploy in firebase ,I got this error.
serviceWorker.js:97
Error during service worker registration: DOMException: Failed to register a ServiceWorker for scope ('https://.web.app/') with script ('https://*.web.app/service-worker.js'):
The script has an unsupported MIME type ('text/html').

Answer 1

I had the same problem, and solved following these steps in GitHub issue:
It happened after create-react-app upgraded to version 4.x.
The "fix" was to create a dummy app:
npx create-react-app my-app --template cra-template-pwa-typescript
And copy over the relevant code:
reportWebVitals.ts
service-worker.ts
serviceWorkerRegistration.ts
And don't forget the initialization code in index.tsx.

Answer 2

The serviceWorker.js provided by Create React App is only there to register a service worker file ( say sw.js ). Try the following steps and see if it works:
Create a sw.js file (this file will hold the logic for your service worker) inside the 'public' folder.
Open the serviceWorker.js provided by Create React App and go the definition of the function register.
Follow the code, and go to the line where it registers the service worker. It might be along the lines of
if ("serviceWorker" in navigator) {
navigator.serviceWorker.register('/path/to/sw.js').then()
}
Here change the /path/to/sw.js to the file you created in the 'public' directory as /sw.js. This corresponds to hostname.com/sw.js
Do this and the service worker might get registered. Things become more complicated from here.
GlHf