Retrieve array of dictionary from Firebase & Swift 3 - ios

Question

I have a json database on firebase and trying to get them and put into local array of dictionaries.
My json model on Firebase
My struct model is also like below
struct Places {
var type:String!
var country:String!
var name:String!
var image:String!
var coords:[Coords]!
init(type: String, country: String, name: String, image: String, coords: [Coords]) {
self.type = type
self.country = country
self.name = name
self.image = image
self.coords = coords
}
init(snapshot: FIRDataSnapshot) {
let snapshotValue = snapshot.value as! [String:Any]
type = snapshotValue["type"] as! String
country = snapshotValue["country"] as! String
name = snapshotValue["name"] as! String
image = snapshotValue["image"] as! String
coords = snapshotValue["coords"] as! [Coords]!
}
}
And also [Coords] struct model like below:
struct Coords {
var latStart:String!
var latEnd:String!
var lonStart:String!
var lonEnd:String!
init(latStart: String, latEnd: String, lonStart: String, lonEnd: String) {
self.latStart = latStart
self.latEnd = latEnd
self.lonStart = lonStart
self.lonEnd = lonEnd
}
}
And I am trying to get and put json data by below code:
placesRef.observeSingleEvent(of: .value, with: { (snapshot) in
if !snapshot.exists() {
print("data not exist")
return
}
var plc: [Places] = []
for eachPlace in (snapshot.children){
let place = Places(snapshot: eachPlace as! FIRDataSnapshot)
plc.append(place)
}
self.allPlaces = plc
The problem is that I can get the array of dictionary except coords dictionary inside array of dictionary. [Coords] dictionary seems null and I would like to know what the problem is. Thanks for any suggestion.

Answer 1

Because snapshotValue["coords"] as! [Coords]! are not Coords yet. They are just dictionaries. You have to go through each dictionary in snapshotValue[“coords”] and init a Coords object, then when you’re finished group them all into an array and assign it to self.coords of the Places struct. The map function is really convenient for this.
Example:
I would change the Coords init function to something like:
init(dictionary: [String : AnyObject]) {
self.latStart = dictionary["lat1"] as? String
//...
//...
}
Then in Places init use something like:
coords = (snapshotValue["coords"] as? [[String : AnyObject]])?.map({ Coord(dictionary: $0) })
I didn't test this and making some assumptions here, but you should be able to make something similar work.