reverseString.js

function reverseWords(messageChars) {
    var word = '';
    var wordStack = [];
    var results = [];
    for (var i = 0, il = messageChars.length; i < il; i++) {
        if (messageChars[i] !== ' ') {
            word += messageChars[i];
        }
        if (messageChars[i] === ' ' || i === il - 1) {
            wordStack.push(word);
            word = '';
        }
    }
    
    for (var i = wordStack.length - 1; i >= 0; i--) {
        results = results.concat(wordStack[i].split(''));
        results.push(' ')
    }
    
    return results;
}

var message = [ 'c', 'a', 'k', 'e', ' ',
                'p', 'o', 'u', 'n', 'd', ' ',
                's', 't', 'e', 'a', 'l' ];

console.log(reverseWords(message).join(''));

console.log(message.join(''));