Evaluate Bool property of optional object in if statement

Question

I am looking for a way to evaluate a Swift Bool concisely in a single if statement, when the Bool is the property of an optional objec

Answer 1

Ah, found it:

if objectWithBool?.bool == true {
    // objectWithBool != nil && bool == true
} else {
    // objectWithBool == nil || bool == false
}

The optional chaining expression objectWithBool?.bool returns an optional Bool. Since it is optional, that expression alone in the if statement would be evaluated to true/false based on whether the optional contains a value or not.

By using the == operator the if statement checks the optional's value, which in this case can be true, false, or nil.

Answer 2

You could also do :

if let obj = objectWithBool where obj {
    // objectWithBool != nil && obj == true
} else {
   // objectWithBool == nil || obj == false
}

Answer 3

Another possible solution is:

if objectWithBool?.bool ?? false {
    println("objectWithBool != nil && objectWithBool.bool == true")
} else {
    println("objectWithBool == nil || objectWithBool.bool == false")
}

The "nil coalescing operator" a ?? b is a shorthand for

a != nil ? a! : b