NSImage to base64 encoded data url

gistfile1.swift

var path: NSString = NSWorkspace.sharedWorkspace().absolutePathForAppBundleWithIdentifier("com.apple.dt.xcode")!
var icon: NSImage = NSWorkspace.sharedWorkspace().iconForFile(path)

var data: NSData = icon.TIFFRepresentation!
var bitmap: NSBitmapImageRep = NSBitmapImageRep(data: data)!
data = bitmap.representationUsingType(NSBitmapImageFileType.NSPNGFileType, properties: [:])!
var base64: NSString = "data:image/png;base64," + data.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.allZeros)
println(base64)