Optional+UseIfNotNil.swift

// Before 😕
let doingSomethingToOptionalView1: CGFloat? = {
  guard let firstSubview = subviews.first else { return nil }
  return (firstSubview.bounds.width / 2.0) + otherView.bounds.width
}()

// After 😊
let doingSomethingToOptionalView2 = subviews.first.useIfNotNil { ($0.bounds.width / 2.0) + otherView.bounds.width }


// ⚙️ Internals
extension Optional {
    /// If the value is not nil, transform it in the specified block. If it is nil, simply returns nil back. Functionally identical to the `map` function on `Optional`, but better named.
    func useIfNotNil<U>(_ transform: (Wrapped) throws -> U) rethrows -> U? {
        switch self {
        case .some(let value):
            return .some(try transform(value))
        case .none:
            return .none
        }
    }
}