Умножить все значения с одни классом jquery

// JS 
var costs = document.querySelectorAll('.cost'); 
var resultCont = document.querySelector('.result'); 
var result = Object.keys(costs).reduce(function(inc, current) { 
  return inc * parseInt(costs[current].innerText); 
}, 1); 
resultCont.innerText = result; 
 
//JQ 
 
var $costs = $('.cost'); 
var resultCont = $('.result2'); 
var result2 = 1; 
$costs.each(function(index, item) { 
  result2 *= parseInt($(item).text()); 
}) 
 
resultCont.text(result2);

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> 
<span class="cost">10</span> 
<span class="cost">20</span> 
<span class="cost">30</span> 
<span class="cost">40</span> 
<br> 
Результат:  
<span class="result"></span> 
 
<br> 
Результат JQuery:  
<span class="result2"></span>

let elemArray = document.querySelectorAll('.cost'); 
let sum = Array.from(elemArray).reduce((s, c) => { 
	return s * +c.textContent 
}, 1); 
console.log(sum);

<span class="cost">10</span> 
<span class="cost">20</span> 
<span class="cost">30</span> 
<span class="cost">40</span>