SwiftUIModifiersSetter.swift

struct MyComponent: View {
    var textColor: Color = .black
    var textSize: CGFloat = 12 
}

extension MyComponent {
    func set<V>(_ keypath: WritableKeyPath<Self, V>, to value: V) -> Self {
        var copy = self
        copy[keyPath: keypath] = value
        return copy
    }
}

MyComponent()
    .set(\.textColor, .red)
    .set(\.textSize, 22)