firebase.json

{
  "firestore": {
    "rules": "firestore.rules",
    "indexes": "firestore.indexes.json"
  },
  "hosting": {
    "public": "public",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "rewrites": [
      {
        "source": "**",
        "destination": "/index.html"
      }
    ],
    "headers": [
      // Use 0 max-age for regular js|json since these are only served to developers.
      {
        "source": "**/*.@(js|json|map)",
        "headers": [
          {
            "key": "Cache-Control",
            "value": "public, max-age=0"
          }
        ]
      },
      // Override max-age for js|json files with MD5 checksum in their name to be 1 year.
      {
        "source": "**/*-checksum-*.@(js|json)",
        "headers": [
          {
            "key": "Cache-Control",
            "value": "public, max-age=31536000"
          }
        ]
      },
      {
        "source": "**/favicon.ico",
        "headers": [
          {
            "key": "Cache-Control",
            "value": "public, max-age=2419200"
          }
        ]
      }
    ]
  },
  "functions": {
    "predeploy": "npm --prefix \"$RESOURCE_DIR\" run build"
  }
}