hipsterfy.js

// Write a function `hipsterfy(sentence)` that takes takes a string containing
// several words as input. Remove the last vowel from each word. `'y'` is not a vowel.

function isVowel(char) { 
    return ["a","e","i","o","u"].indexOf(char.toLowerCase()) !== -1; 
}

function hipsterfy(str) {
    return str.split("").reverse().reduce(function(acc, char) {
        if(isVowel(char) && acc.needLastVowel) 
            return { needLastVowel: false, newString: acc.newString };   
        else
            return { needLastVowel: acc.needLastVowel || char === " "
                   , newString: char + acc.newString
                   };        
    }, { needLastVowel: true, newString: ""}).newString;
}

console.log(hipsterfy("proper")); // => "propr"
console.log(hipsterfy("proper tonic panther")); // => "propr tonc panthr"
console.log(hipsterfy("towel flicker banana")); // => "towl flickr banan"
console.log(hipsterfy("runner anaconda")); // => "runnr anacond"
console.log(hipsterfy("turtle cheeseburger fries")); // => "turtl cheeseburgr fris"