JSFiddle - React, Tailwind, and code Playground
by master1991
HTML
<div class="qInDocBXXX AB"></div>
<input type="text" name="valueToAdd" data-item="XXX AB" class="BenterInput">
<a class="btn btn-default btn-xs add_row BXXX AB" data-but="B" style="display: none;">XXX</a>
JavaScript
$(document).on('keyup', ".BenterInput", function() {
var item = $(this).attr('data-item');
var num = $(this).val();
$(`a.B${item.split(" ").join(".")}`).toggle($.isNumeric(num));
});