firebase.site-xy.json

{
  "hosting": {
    "site": "site-xy",
    "public": "build",
    "ignore": ["firebase.json", "**/.*", "**/node_modules/**"],
    "rewrites": [
      {
        "source": "**",
        "destination": "/index.html"
      }
    ],
    "headers": [
      {
        "source": "**",
        "headers": [{ "key": "Cache-Control", "value": "max-age=300" }]
      },
      {
        "source": "static/**",
        "headers": [{ "key": "Cache-Control", "value": "max-age=31536000" }]
      }
    ]
  }
}