Face ID evaluation process not working properly

Question

I\'m trying to get if Face ID or Touch ID succeeded in the function below

func authenticate() -> Bool{

    let context = LAContext()
    var error: NSErr         


        

Answer 1

You should use a closure to obtain results of evaluation. Note that the return value for canEvaluatePolicy is a Bool but there is no return value for evaluatePolicy as it accepts a closure.

You can modify your method to include a closure instead of return.

func authenticate(completion: ((Bool) -> ())) {
    ...
    completion(true) // false if it failed.
    ...
}

In other parts of your app, where you earlier used a return value you would now have to use a closure like:

class Foo {
   func test() {
       let isEvaluated = self.authenticate() // Old way
       self.authenticate { success in
           // bool will now indicate whether evaluation was done successfully or not.
       }
   }
}