Question: My intention is to set two different max length values to two input fields, `notifTitle` and `notifDescribtion`. 

So far I have:

```
 extension CreateNotViewController: UITextFieldDelegate {
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let maxLength = 15
        let currenString: NSString = textField.text! as NSString
        let newString: NSString = currenString.replacingCharacters(in: range, with: string) as NSString

        return newString.length <= maxLength
    }
}

```

```
override func viewDidLoad() {
        super.viewDidLoad()
        notifTitle.delegate = self
        ...
    }

```

Now if I also add `notifDescribtion.delegate = self`, its max length is also set to 15 characters. How am I able to set the max length individually for each input field.

Answer: 
Since `[value]` needs a string, you could set its value to

```
[value]="period.month + '/' + period.year"

```

which resolves to a string. In your code, `period.month` is divided by `period.year` and resolves to `NaN` if at least one of them cannot be changed to a number.
I think`[value]` only supports strings. Try `[ngValue]` instead.

[Differences between value and ngValue in Angular 5](https://stackoverflow.com/questions/49918687/differences-between-value-and-ngvalue-in-angular-5)