firebase.json

{
  "database": {
    "rules": "database.rules.json"
  },
  "functions": {
    "predeploy": [
      "npm --prefix \"$RESOURCE_DIR\" run lint",
      "npm --prefix \"$RESOURCE_DIR\" run build"
    ]
  },
  "hosting": {
    "public": "out",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "rewrites": [
      {
        "source": "/authorize",
        "destination": "/authorize.html"
      },
      {
        "source": "/error",
        "destination": "/error.html"
      },
      {
        "source": "/",
        "destination": "/index.html"
      },
      {
        "source": "/**",
        "function": "urlShortener"
      }
    ]
  },
  "emulators": {
    "auth": {
      "port": 9099
    },
    "functions": {
      "port": 5001
    },
    "database": {
      "port": 9000
    },
    "hosting": {
      "port": 5000
    },
    "ui": {
      "enabled": true
    }
  }
}