firebase.json

{
  "firestore": {
    "rules": "firestore.rules",
    "indexes": "firestore.indexes.json"
  },
  "functions": {
    "predeploy": [
      "npm --prefix \"$RESOURCE_DIR\" run lint",
      "npm --prefix \"$RESOURCE_DIR\" run build"
    ]
  },
  "hosting": {
    "public": "dist",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "headers": [{
      "source": "**",
      "headers": [
        { "key" : "Access-Control-Allow-Origin", "value" : "*" },
        { "key" : "X-Frame-Options", "value" : "deny" },
        { "key" : "X-Content-Type-Options", "value" : "nosniff" },
        { "key" : "X-XSS-Protection", "value" : "1; mode=block" },
        { "key" : "X-Permitted-Cross-Domain-Policies", "value" : "none" },
        { "key" : "Referrer-Policy", "value": "no-referrer" }
      ]
    }],
    "rewrites": [
      {
        "source": "/ja/**",
        "destination": "/index-ja.html"
      },
      {
        "source": "**",
        "destination": "/index.html"
      }
    ]
  },
  "storage": {
    "rules": "storage.rules"
  },
  "emulators": {
    "firestore": {
      "port": 8090
    },
    "storage": {
      "port": 9199
    },
    "ui": {
      "enabled": true
    },
    "auth": {
      "port": 9099
    },
    "functions": {
      "port": 5002
    },
    "hosting": {
      "port": 5001
    },
    "pubsub": {
      "port": 8085
    }
  }
}