Create or open a Swift Playground through Alfred.
Install the workflow then open Alfred and type swift and press enter. This will create a folder ~/Playgrounds/Default and then open a playground named default.playground in XCode. The next time you open Alfred and type swift this playground will be opened.
Alternatively you can pass in a parameter to swift and that playground will either be created if it doesn't already exist or opened if it does. e.g. swift spriteKitTest