String+isNilOrEmpty.swift

//String extension that checks for an empty (after trimming whitespace) or nil string:
//
// Usage: var isEmpty = String.isNilOrEmpty(myString)
//
// Credit to: Kevin McNeish
// http://iosappsfornonprogrammers.com/forum/index.php?topic=1836.0

extension String {
   public static func isNilOrEmpty(string: String?) -> Bool {
        
        switch string?.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet()) {
        case .Some(let nonNilString):
            return nonNilString.isEmpty
        default:
            return true
        }
    }
}