“Funkcja Hosting FireBase Rewrite musisz włączyć JavaScript uruchomienie tej aplikacji.” Kod odpowiedzi

Funkcja Hosting FireBase Rewrite musisz włączyć JavaScript uruchomienie tej aplikacji.

The issue could be due to the order of your firebase.json rewrites. If 
{
  "source": "**",
  "destination": "/index.html"
}
is at the top of your rewrites then everything will match the "**" wildcard first, which is not what we want.

Instead, put the api (or whatever) rewrites first and put "**" last. E.g:
"rewrites": [
  {
    "source": "/api/**",
    "function": "api"
  },
  {
    "source": "**",
    "destination": "/index.html"
  }
]
This way the "/api/**" route is caught first and then everything else falls through. (Obvious in hindsight...)

Hope this helps save someone else a few hours!