reader/backend/firebase.json

{
  "firestore": {
    "rules": "firestore.rules",
    "indexes": "firestore.indexes.json"
  },
  "functions": [
    {
      "source": "functions",
      "codebase": "default",
      "ignore": [
        "node_modules",
        "src",
        ".git",
        "*.log",
        "*.local",
        ".secret.*",
        ".firebase-emu"
      ],
      "predeploy": [
        "npm --prefix \"$RESOURCE_DIR\" run build:clean",
        "npm --prefix \"$RESOURCE_DIR\" run build"
      ]
    }
  ],
  "storage": {
    "rules": "storage.rules"
  },
  "emulators": {
    "ui": {
      "enabled": true
    },
    "singleProjectMode": true,
    "functions": {
      "port": 5001
    },
    "firestore": {
      "port": 9098
    },
    "storage": {
      "port": 9097
    }
  }
}