Array Elements Triple and Join

tripleArrElements.js

// Given an array ["foo", "bar", "baz"],
// return ["foo foo foo", "bar bar bar", "baz baz baz"]

var arr = ["foo", "bar", "baz"];

function triple(element) {
    return [element, element, element].join(" ");
}

arr.forEach(function() {
    arr.unshift(triple(arr.pop()));
});

console.log(arr);​