AttributedStringParagraphExtensions.swift

extension NSAttributedString {
  func align(_ alignment: NSTextAlignment) -> NSAttributedString {
    
    //1
    guard !string.isEmpty else { return self }
       
    //2
    let mutable = mutableCopy() as! NSMutableAttributedString
    
    //3
    let style = mutable.attribute(NSParagraphStyleAttributeName, at: 0, longestEffectiveRange: nil, in: NSMakeRange(0, string.characters.count)) as? NSParagraphStyle
    
    //4
    let pStyle = (style?.mutableCopy() as? NSMutableParagraphStyle) ?? NSMutableParagraphStyle()
    
    //5
    pStyle.alignment = alignment
    
    //6
    let attribute = [
      NSParagraphStyleAttributeName : pStyle
    ]
    
    //7
    mutable.addAttributes(attribute, range: NSRange(location: 0, length: string.characters.count))
        
    return mutable
  }
}

//Example Usage
"Style me"
  .toAttributedString()
  .medium(sized: 16)
  .colored(.orange)
  .align(.center)