JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="foo" value="" disabled="disabled" />
<ul data-change="#foo">
    <li><button id="i" data-value="i">i</button></li>
    <li><button id="a" data-value="a">a</button></li>
</ul>

JavaScript

$('[data-change] button').on('click', function(){
    var target = $(this).closest('[data-change]').data('change');
   $(target).val( $(target).val() + $(this).data('value') );
});