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iOS Generics in Swift Generics and Protocols Extending Generic Types

Make sure you're adding the filter(byPrefix:) function to the extension of Array

keep saying that even adding it

protocol PrefixContaining {
  func hasPrefix(_ prefix: String) -> Bool
  func filter(byPrefix prefix: String) -> [Element]

extension Array where Element: PrefixContaining {

    var element: Array  {Element.hasPrefix

        return self


    var string: String {Element.filter("a")

    return [Element]