refactor
by Dmitry Morar
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="text" class="cat" value="1">
<div id="dima">
<button class="plus">+</button>
<button class="minus">-</button>
</div>
JavaScript
let inputAmount = $('.cat');
$(".plus").click(function() {
let quantity = parseInt(inputAmount.val(), 10);
inputAmount.val(quantity + 1);
});
$(".minus").click(function() {
let quantity = parseInt(inputAmount.val(), 10);
inputAmount.val(quantity - 1);
});