firebase.json

{
  "firestore": {
    "rules": "firestore.rules",
    "indexes": "firestore.indexes.json"
  },
  "hosting": {
    "public": "build",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "headers": [
      {
        "source": "**/*",
        "headers": [
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "https://your-cors-anywhere-server-link.com/https://api.cryptowat.ch/",
        "headers": [
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "https://api.coingecko.com/",
        "headers": [
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "*",
        "headers": [
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "**",
        "headers": [
          {
            "key": "Access-Control-Allow-Origin",
            "value": "*"
          }
        ]
      },
      {
        "source": "**/*.@(js)",
        "headers": [ {
          "key": "Access-Control-Allow-Origin",
          "value": "*"
        } ]
      }
    ],
    "rewrites": [
      {
        "source": "**",
        "destination": "/index.html"
      }
    ]
  },
  "storage": {
    "rules": "storage.rules"
  }
}