What is the nature of a class property when declared with "= {}()" in Swift?

Question

I have a Swift class from some sample code, and within it there is a property captureSession declared like so:

private lazy var captureSession: AVCaptureSession = {
    let session = AVCaptureSession()

    guard
        let backCamera = AVCaptureDevice.default(for: .video),
        let input = try? AVCaptureDeviceInput(device: backCamera)
        else { return session }
    session.addInput(input)
    return session
}()

I don't think captureSession is a computed property, neither is it a closure. Then what is it?

Answer 1

captureSession is lazy property but ={}() is not regarding lazy initialization. It is Setting a Default Property Value with a Closure or Function. This is an example.

let titleLabel: UILabel = {
    let label = UILabel()
    label.numberOfLines = 0
    label.textColor = UIColor.textColor
    label.font = UIFont(name: "HelveticaNeue-Medium", size: 14)
    return label
}()

You can find more information at the end of this document.