how to add two numbers in list using sightly

Question

I have requirement to add numbers present in list and if count is greater than 12 i need to add extra div i html.I am able to do this in jsp.But how can be acheive this in sightly.if i write count logic in java how can i add the extra div in html

Below is code in jsp

<c:forEach items="${colValues}" var="colValue">
                        <c:set var="lgHidden" value=''/>
                        <c:set var="mdHidden" value=''/>
                        <c:set var="smHidden" value=''/>
                        <c:set var="xsHidden" value=''/>
                        <fmt:parseNumber var="lgValue" type="number" value="${colValue['large']}" />
                        <fmt:parseNumber var="lgCount" type="number" value="${lgValue+lgCount}" />
                        <c:if test="${lgCount>12}">
                         <fmt:parseNumber var="lgCount" type="number" value="${lgValue}" />
                         <div class="clearfix visible-lg-block"></div>
                          </c:if>

The above coddee is fine in jsp.But how to add two variables in sightly

Answer 1

As per the spec Sightly does not support operations inside expressions. You would need to create a helper use-object (using either JavaScript or Java) that would provide the test threshold/reference value.