// Given a string, cycle the first letter of each word back one word,
// and cycle the last letter of each word forward one word.

// Example input:  "who welld horly"
// Example output: "why hello world"

// Do this example by hand:
// Input:  "bes le uoogit"
// Output: ""

let recycle = (str) => {
	str = str.split(" ");
	let sol = [];
	for(let i=0; i<str.length; i++){
		sol.push(str[i + 1 > str.length - 1 ? 0 : i + 1].charAt(0) + str[i].slice(1, str[i].length - 1) + str[i - 1 < 0 ? str.length - 1 : i - 1][str[i - 1 < 0 ? str.length - 1 : i - 1].length - 1]);
	}
	return sol.join(" ");
}

console.log(recycle("who welld horly"));