joined for AttributedString

joined.swift

// split / join for attributed string
extension Sequence where Iterator.Element: NSAttributedString {
    func joined(separator: NSAttributedString = NSAttributedString(string: "")) -> NSAttributedString {
        var isFirst = true
        return self.reduce(NSMutableAttributedString()) {
            (r, e) in
            if isFirst {
                isFirst = false
            }
            else {
                r.append(separator)
            }
            r.append(e)
            return r
        }
    }
    
    func joined(separator: String = "") -> NSAttributedString {
        let separator = NSAttributedString(string: separator)
        return joined(separator: separator)
    }
}