RecursivelyGlowInTheDarkViewModifier.swift

struct RecursivelyGlowInTheDarkViewModifier: ViewModifier {
    let colors: [Color]
    func body(content: Content) -> some View {
        var modifiedColors = colors // First create a local variable
        let nextColor: Color?
        if !modifiedColors.isEmpty { // if it is not empty, remove the first element to use it
            nextColor = modifiedColors.remove(at: 0)
        } else { // or set as nil
            nextColor = nil
        }
        
        // calling the builder
        return buildView(content: content, nextColor: nextColor, colors: modifiedColors)
    }
    
    // Using @ViewBuilder to accept different results type
    @ViewBuilder private func buildView(content: Content, nextColor: Color?, colors: [Color]) -> some View {
        if let color = nextColor {
            // in the case it has more colors, it adds the shadow and call the modifier again
            content
                .shadow(color: color, radius: 5)
                .modifier(RecursivelyGlowInTheDarkViewModifier(colors: colors))
        } else {
            // otherwise it only returns the view without modifier
            content
        }
    }
}