Firebase CLI: "Configure as a single-page app (rewrite all urls to /index.html)"

Question

I just used the Firebase CLI to init a static hosting project. What exactly happens when you enable the "configure as a single-page app" option? I'm looking for a description of exactly which files are modified, and what kind of effect this has on the Firebase backend.

Answer 1

That option simply sets a flag in the firebase.json file to redirect all URLs to /index.html.

"rewrites": [ {
  "source": "**",
  "destination": "/index.html"
} ]

See the documentation of Firebase Hosting for more information, which also contains this fuller example:

"hosting": {
  // ...

 // Add the "rewrites" attribute within "hosting"
  "rewrites": [ {
    // Serves index.html for requests to files or directories that do not exist
    "source": "**",
    "destination": "/index.html"
  }, {
    // Serves index.html for requests to both "/foo" and "/foo/**"
    // Using "/foo/**" only matches paths like "/foo/xyz", but not "/foo"
    "source": "/foo{,/**}",
    "destination": "/index.html"
  }, {
    // Excludes specified pathways from rewrites
    "source": "!/@(js|css)/**",
    "destination": "/index.html"
  } ]
}