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": "public",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "headers": [
      {
        "source": "/api/order",
        "headers": [
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }, {
            "key": "Access-Control-Allow-Methods",
            "value": "POST, OPTIONS"
          }, {
            "key": "Access-Control-Allow-Headers",
            "value": "Origin,  X-Requested-With, Content-Type, Accept"
          }
        ]
      },
      {
        "source": "/api/order/:id",
        "headers": [
          {
            "key": "Cache-Control",
            "value": "max-age=20"
          },
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "/api/pairs",
        "headers": [
          {
            "key": "Cache-Control",
            "value": "max-age=3600"
          },
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "/api/rate/:deposit/:receive",
        "headers": [
          {
            "key": "Cache-Control",
            "value": "max-age=10"
          },
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      }
    ],
    "rewrites": [
      {
        "source": "/api/order{,/*}",
        "function": "order"
      },
      {
        "source": "/api/pairs",
        "function": "pairs"
      },
      {
        "source": "/api/rate/:deposit/:receive",
        "function": "rate"
      }
    ]
  }
}