Check string for nil & empty

Question

Is there a way to check strings for nil and \"\" in Swift? In Rails, I can use blank() to check.

I currently have this, but i

Answer 1

With Swift 5, you can implement an Optional extension for String type with a boolean property that returns if an optional string is empty or has no value:

extension Optional where Wrapped == String {

    var isEmptyOrNil: Bool {
        return self?.isEmpty ?? true
    }

}

However, String implements isEmpty property by conforming to protocol Collection. Therefore we can replace the previous code's generic constraint (Wrapped == String) with a broader one (Wrapped: Collection) so that Array, Dictionary and Set also benefit our new isEmptyOrNil property:

extension Optional where Wrapped: Collection {

    var isEmptyOrNil: Bool {
        return self?.isEmpty ?? true
    }

}

---

Usage with Strings:

let optionalString: String? = nil
print(optionalString.isEmptyOrNil) // prints: true

let optionalString: String? = ""
print(optionalString.isEmptyOrNil) // prints: true

let optionalString: String? = "Hello"
print(optionalString.isEmptyOrNil) // prints: false

Usage with Arrays:

let optionalArray: Array? = nil
print(optionalArray.isEmptyOrNil) // prints: true

let optionalArray: Array? = []
print(optionalArray.isEmptyOrNil) // prints: true

let optionalArray: Array? = [10, 22, 3]
print(optionalArray.isEmptyOrNil) // prints: false

---

Sources:

• swiftbysundell.com - Extending optionals in Swift
• objc.io - Swift Tip: Non-Empty Collections