ES6 Map var fruits = ['apple', 'orange', 'banana'] var onlyCouscous = fruits.map do |fruit| return 'couscous' console.log onlyCouscous # ["couscous", "couscous", "couscous"] Function with multiple parameters def giveFruits fruit1, fruit2 console.log "I love {fruit1} and {fruit2}" giveFruits 'apple','orange' # I love apple and orange Anonym function var sayHello = do |name1, name2| console.log "Hello {name1} & {name2}" sayHello 'Frank','Guillaume' # Hello Frank & Guillaume Function with default parameter def sayUniverseResponse response = 42 console.log "Response of the universe is {response}" sayUniverseResponse # Response of the universe is 42