<div class="row js-stepper">
  <div class="col-xs-6 col-sm-3 col-md-2 col-all-closer col-all-closer--leftend">
    <div class="form-group">
      <label><span class="label-text">数量</span></label>
      <input type="text" class="form-control text-right" value="1">
    </div>
  </div>
  <div class="col-xs-6 col-sm-3 col-md-2 col-all-closer col-all-closer--rightend">
    <div class="form-group">
      <div class="btn-group btn--ls">
        <button type="button" class="btn btn-inverse js-stepper--minus"><span class="icon-abui-minus"></span></button>
        <button type="button" class="btn btn-inverse js-stepper--plus"><span class="icon-abui-plus"></span></button>
      </div>
    </div>
  </div>
</div>

const stepnum = 1;
$('.js-stepper').find('.btn-group button').on('click', function() {
  const $field = $('.js-stepper').find('input[type="text"]');
  let val = parseInt($field.val());
  if ($(this).hasClass('js-stepper--minus')) {
    val = val - stepnum;
  } else if ($(this).hasClass('js-stepper--plus')) {
    val = val + stepnum;
  };
  $field.val(val);
});