JSFiddle - React, Tailwind, and code Playground

HTML

<form action="">
    <input type="text">
    <br />
    <button class="save-form" type="submit" disabled="disabled">submit</button>
</form>

JavaScript

$(function() {
    $('form > input').keyup(function() {
        var empty = false;

        $('form > input').each(function() {
            if ($(this).val().trim() == '') {
                empty = true;
            }
        });

        $('.save-form').prop('disabled', empty);
    });
});