Egorian

function func(array) {
 return array
}

console.log(func(arr)) //(3) ["Hello", "Name", "lastName"]
console.log(func()) //undefined
console.log(func) //ƒ func(array) {return array}

<div class="first-ul">
       <ul>
           <li><span>1</span></li>
           <li><span>2</span></li>
       </ul>
   </div>
   <div class="second-ul">
      <ul>
       <li><span class="data-container"></span><span>text</span></li>
       <li><span class="data-container"></span><span>text</span></li>
       </ul>
   </div>
   <script type="text/javascript">
    var data=$(".first-ul ul li span");
    for (i=0;i<data.length;i++){
        $(".second-ul .data-container").eq(i).text(data.eq(i).text())
    }   
    
    </script>