TypeError: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script.

[ganesh-phadtare]

Browser : chrome v65.0.3325.181

I am facing an issue as TypeError: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script. This issue is occurring when I execute command as
ng build -- prod

Detail error is like
main.27194690c35d3972faa9.bundle.js:1 ERROR Error: Uncaught (in promise): TypeError: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script.
TypeError: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script.

and when I inspect the chrome browser - in the network tab "ngsw-worker.js" is showing the status as failed.

[stephenlautier]

I just tried it again and it seems that its working fine.

npm i
npm run start:prod

Dont use ng build -- prod (you have a typo there)

Did you update anything or recreated lock file perhaps?

[stephenlautier]

Recreated package lock and it still working fine, use the command i suggested and see if it works

[BLecha]

@stephenlautier but if I one needs to use ng build --prod?

[stephenlautier]

@BLecha you can, it just need to be written properly.

As commented above, either use

# shorthand
npm run start:prod

# or else 
npm run build -- --prod

# or as you wrote it directly (but becareful because that uses the global)
ng build --prod

[BLecha]

@stephenlautier have you deployed angular pwa app on local IIS?