JSFiddle - React, Tailwind, and code Playground

HTML

<div class="cart-item-info much">
                                        <a href="#" class="jsminus">-</a>
                                        <input type="text" value="1" id="input1">
                                        <a href="#" class="jsplus">+</a>
                                    </div>

CSS

.much a {
  padding: 2px;
  border: 1px solid #e5e5e5;
  text-decoration: none;
}
.much .jsminus {
  background: #d73339;
  color: #ffffff;
  margin-right: -5px;
}
.much .jsplus {
  background: #d73339;
  color: #ffffff;
  margin-left: -5px;
}

JavaScript

$( ".jsminus" ).click(function(){
    var much = +$(this).closest(".much").find("input").val();
    var result = much - 1;
    $(this).closest(".much").find("input").val(result)
    return true;
});
$( ".jsplus" ).click(function(){
    var much = +$(this).closest(".much").find("input").val();
    var result = much + 1;
    $(this).closest(".much").find("input").val(result)
    return true;
});