I would like to create model which has optional values.
I implemented
flatmap
"Post": {
"uid": {
"autoid"{
"Text": "some text",
"Date": "some date",
"imageUrl": {
autoID1: url1,
autoID2: url2
}
},
"autoid"{
"Text": "some text",
"Date": "some date"
}
}
}
import UIKit
import Firebase
extension DataSnapshot {
var snapshots: [DataSnapshot] {
return children.allObjects.flatMap({ $0 as? DataSnapshot })
}
var string: String? { return value as? String }
var url: URL? { return string.flatMap({ URL(string: $0) }) }
var urls: [URL] { return snapshots.flatMap({ $0.url }) }
}
struct Post {
let snapshot: DataSnapshot?
var Date: String!
var imageUrl: [URL]?
var Text: String!
init(snapshot: DataSnapshot) {
self.snapshot = snapshot
self.Date = snapshot.child["Date"].string
self.imageUrl = snapshot.child["imageUrl"].urls
self.Text = snapshot.child["Text"].string
}
}
init
Value of type 'DataSnapshot' has no member 'child'
DataSnapshot
doesn't have the member child
, doc here.
So to be able to extract something from the DataSnapshot
, you might use this idea:
if let value = snapshot.value as? [String: Any] {
self.Date = value["Date"] as? String ?? ""
self.Text = value.child["Text"] as? String ?? ""
// extracting the urls
if let urls = value.child["tweetImageUrl"] as? [String:String] {
self.imageUrl = urls.flatMap { k,v in URL(string:v) }
}
}
Note that:
flatMap
is awesome because provide the possibility to skip automatically all the iterations that are returning an optional value.