function that duplicates an array

duplicate-array.js

 // function that duplicates an array
 function duplicateArray(arr) {
    // create clone of original array using slice
    var cloneArr = arr.slice(); 
    // concat original array and clone array in one new array (the objective!!)
    var dupArr = arr.concat(cloneArr);
    //return the new array
    return dupArr;
}