Completion handler and if statement within - swift

Question

I wrote a function that I guess it should return a boolean , I'm using completion handler and switch and if statements within
this is my code :
class func login(username : String , password : String, _ completion: #escaping (Bool) -> ()) {
let url = "http://127.0.0.1:3000/login/"+username+"/"+password
Alamofire.request(url).responseJSON{response in
switch response.result
{
case .failure:
print(response)
completion(false)
case .success:
if let dict = response.value as? NSDictionary {
let dict = response.value as? NSDictionary
let user = dict!["users"] as? NSArray
if user!.count > 0 {
print(user!.count)
completion(true)
}
else {
print(user!.count)
completion(true)
}
}
}
}
}
And I want to use it like this :
#IBAction func LoginBtn(_ sender: Any) {
API.login(username: textUsername.text!, password: textPassword.text!) {
success in
if success{
// if the function return true print(hello)
//else print (type again)
print("Welcome")
}
else{
print("NO")
}
}
}

Answer 1

First of all don't use NSArray and NSDictionary in Swift, use native types.
Second of all never use .count > 0 to check for empty array or empty string. There is an optimized property isEmpty
Your code is very cumbersome and there are a few redundant parts in it.
The logic is to return true if the users array is valid and not empty otherwise return false.
So the success branch can be reduced to
case .success:
if let dict = response.value as? [String:Any], let users = dict!["users"] as? [[String:Any]], !users.isEmpty {
completion(true)
} else {
completion(false)
}