CODEWITHSUNDEEP
swiftfirebasefirebase-realtime-database
PerNil
PerNil

Reputation: 187

Failing to check if result of query is nil

I have a query that checks if a phoneNumber exists in the child "visitors". If the phoneNumber exists, it adds the key of the child to the variable visitorID
If the visitorID != "" I get the code to do what I want, but when visitorID == "" I cannot get the code to do anything. Here's my best effort: 

ref?.child("visitors").queryOrdered(byChild: "phoneNumber").queryEqual(toValue: phoneNumber).observeSingleEvent(of: .value, with: { (snapShot) in

   if let snapDict = snapShot.value as? [String:AnyObject]{
       var visitorID = String()        
       for each in snapDict{
           let key  = each.key as! String               
           visitorID = key    
       }

       if visitorID != "" {        
           //Do something       
       } else {         
           //Do something else        
       }    
   }    
}, withCancel: {(Err) in
    print(Err.localizedDescription)
})

Upvotes: 0

Views: 33

Answers (1)

Jay
Jay

Reputation: 35648

If you want to perform a query and determine if there are any results, snapshot.exists is what you want

ref?.child("visitors").queryOrdered(byChild: "phoneNumber").queryEqual(toValue: phoneNumber).observeSingleEvent(of: .value, with: { (snapshot) in

   if snapshot.exists() {
      print("found at least one")
      //do something with snapshot
   } else {
      print("non found, returning")
      return
   }

}, withCancel: {(Err) in
    print(Err.localizedDescription)
})

or

ref?.child("visitors").queryOrdered(byChild: "phoneNumber").queryEqual(toValue: phoneNumber).observeSingleEvent(of: .value, with: { (snapshot) in

   if snapshot.exists() == false {
      print("none found, returning")
      return
   }
   //do something with snapshot

Upvotes: 1

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