Swift: joined() for Array of NSAttributedString?

Question

In Swift, you can join an Array of String like so:

let a = ["fee", "fi", "fo", "fum"]
print(a.joined(separator: " ")) // -> "fee fi fo fum"

How can I join an Array of NSAttributedString like this?

Answer 1

This extension adds the ability to join an Array of NSAttributedString, as you would with Strings.

extension Array where Element: NSAttributedString {
  func joined(separator: NSAttributedString) -> NSAttributedString {
    guard let firstElement = first else { return NSAttributedString() }

    return dropFirst()
      .reduce(into: NSMutableAttributedString(attributedString: firstElement)) { collector, element in
        collector.append(separator)
        collector.append(element)
      }
  }

  func joined(separator: String = "") -> NSAttributedString {
    joined(separator: NSAttributedString(string: separator))
  }
}