Can Swift 4's JSONDecoder be used with Firebase Realtime Database?

Question

I am trying to decode data from a Firebase DataSnapshot so that it can be decoded using JSONDecoder.

I can decode this data fine when I use a URL to access it with a

Answer 1

You can convert the value returned by Firebase to Data, and then decode that.

Add this extension to your project:

extension Collection {
    //Designed for use with Dictionary and Array types
    var jsonData: Data? {
        return try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
    }
}

Then use it to convert the value of the observed snapshot into data, which can then be decoded:

yourRef.observe(.value) { (snapshot) in
    guard snapshot.exists(),
       let value = snapshot.value as? [String],
       let data = value.jsonData else { 
       return
    }
    //cast to expected type
    do {
        let yourNewObject =  try JSONDecoder().decode([YourClass].self, from: data)
    } catch let decodeError {
        print("decodable error")
    }
}