Getting value of children with same name - Firebase Swift3 - swift

Question

I'm using the following query to get the snapshot below.
dbRef.child("users").queryOrdered(byChild: "username").queryStarting(atValue: text).queryEnding(atValue: text+"\u{f8ff}").observe(.value, with: { snapshot in })
But I'm having trouble figuring out how to iterate over the values of the children "username" (i.e. bill, billy, billykins) because they all have the same key ("username"). I'm trying to extract all the names and put them in an array of names.
Snap (users) {
fDrzmwRUt2guh3O8pc792ipyEqA3 = {
username = bill;
};
qyQkIOxSpXgQoUoh0QNvPlkQ1Mp1 = {
username = billy;
};
edSk54xSpXgQoYoh0QNvOlkQ1Mp3 = {
username = billykins;
};
}
This is my function which gets the snapshot and tries to iterate over it. However, the loop crashes:
func findUsers(text: String) {
print("search triggered")
dbRef.child("users").queryOrdered(byChild: "username").queryStarting(atValue: text).queryEnding(atValue: text+"\u{f8ff}").observe(.value, with: { snapshot in
print(snapshot)
for i in snapshot.children{
let value = snapshot.value as! Dictionary<String,String>
let username = value["username"]
print(username)
self.userList.append(username!)
print(self.userList)
}
}) { (error) in
print("searchUsers \(error.localizedDescription)")
}
}
Here's a fraction of the log. Too long to post:
0x1002cg360 <+272>: adr x9, #268929 ; "value type is not bridged to Objective-C"
0x1002cg364 <+276>: nop
0x1002cg368 <+280>: str x9, [x8, #8]
-> 0x1002cg36c <+284>: brk #0x1
0x1002cg370 <+288>: .long 0xffffffe8 ; unknown opcode

Answer 1

Here's the solution I was looking for. I needed to loop through the big snapshot to extract the child snapshots into an array, and then loop through the child snapshots by value to get the usernames:
func findUsers(text: String) {
print("search triggered")
dbRef.child("users").queryOrdered(byChild: "username").queryStarting(atValue: text).queryEnding(atValue: text+"\u{f8ff}").observe(.value, with: { snapshot in
print(snapshot)
if ( snapshot.value is NSNull ) {
print("not found")
} else {
var blaArray = [FIRDataSnapshot]()
for child in snapshot.children {
let snap = child as! FIRDataSnapshot //downcast
blaArray.append(snap)
}
for child in blaArray {
let dict = child.value as! NSDictionary
let username = dict["username"]!
print(username)
}
}) { (error) in
print("searchUsers \(error.localizedDescription)")
}
}
Adapted from this post: Get data out of array of Firebase snapshots