this code fix the problem of update the quantity automatically when the theme use a different quantity field
var request;
$(document).on( 'click', '.product-quantity input', function(e){
if( typeof request !== 'undefined' ){
request.abort();
}
var $t = $(this),
$input_quantity = $t.closest('.product-quantity').find('.input-text.qty'),
name = $input_quantity.attr('name'),
value = $input_quantity.val(),
item_keys = name.match(/[^[\]]+(?=])/g);
//this is not necessary for some theme like flatsome
if( $t.hasClass('plus') ){
value ++;
}
if( $t.hasClass('minus') ){
value --;
}
//end
var request_info = 'action=yith_ywraq_action&ywraq_action=update_item_quantity&quantity='+value+'&key='+item_keys[0];
request = $.ajax({
type : 'POST',
url : ywraq_frontend.ajaxurl.toString().replace( '%%endpoint%%', 'yith_ywraq_action' ),
dataType: 'json',
data : request_info
});
});