JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
<form class="form" name="searchForm" method="post">
  <input id="query" placeholder="Search something" type="text" name="query">
  <input id="submit" type="submit" value="Send" disabled="disabled">
</form>

JavaScript

$('#query').keyup(function () {
    if ($(this).val() == '') {
        $('#submit').prop('disabled', true);
    } else {
        $('#submit').prop('disabled', false);
    }
}).keyup();