Swift Shortcut: ??
Before the ?? operator was added to Swift, you would use a ternary conditional operator and forced unwrapping to assign a default value if the expected value is nil.
let bossMonster = (monster != nil monster! : defaultMonster)
// this code says that if monster is not nil then force unwrap monster to get its value, otherwise use defaultMonster
?? provides a shortcut to the above.
let bossMonster = monster ?? defaultMonster
Short and simple! The ?? is known as the nil coalescing operator.