Firebase function for sitemap.xml

Step 1

Deploy this code to google cloud function https://cloud.google.com/functions/docs/deploying

Set sitemapGenerator as entry point

Step 2

Setup API_SITEMAP_URL ENV variable https://cloud.google.com/functions/docs/configuring/env-var

Step 3

Just add to firebase.json

"rewrites": [
  {
    "source": "/sitemap.xml",
    "function": "yourFunctionName"
  },
]