What is Swift If Case

What is If Case syntax in Swift

if-case is a Swift syntax to match only a single case of an enum.

Here is an example enum, Direction.

enum Direction {
    case north
    case south
    case east
    case west
}

We can use if-case to match a single case like this.

let direction = Direction.north

if case .north = direction {
    print("North")
} else {
    print("Wrong direction")
}

Here is the equivalent version of a switch statement.

switch direction {
case .north:
    print("North")
case .south, .east, .west:
    print("Wrong direction")
}

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How to use If Case syntax

if-case has the following syntax.

• The case pattern goes after an if statement.
• The case pattern followed by the assignment (=) statement.

Here is how it looks.

if case pattern = enumValue {}

The case pattern has the same syntax as the switch statement. You can use any pattern that is supported in the switch statement.

Let's see some examples.

In the following examples, we will use an enum with an associated value, Barcode.

enum Barcode {
    case basic(Int)
    case qrCode(String)
}

If case

We can use if-case to match a single case with the following syntax.

let code = Barcode.qrCode("sarunw")
        
if case .qrCode = code {
    print("QR Code")
} else {
    
}

If case let

And just like a normal switch statement, we can use let to bind the associated value of that enum.

let code = Barcode.qrCode("sarunw")

if case let .qrCode(content) = code {
    print("QR Code: \(content)")
} else {
    
}

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Why do we need If Case

The switch statement syntax forces you to handle all of the cases.

This is a good thing since it makes sure you always handle every case. The compiler will warn us when we introduce a new case or remove an old one.

The only time you will need to use the if-case syntax is when you only care about one specific case.