JSFiddle - React, Tailwind, and code Playground
HTML
<input id=field />
<ul id=log>
JavaScript
$('#field').keyup(function() {
var $field = $(this);
// this is the value before the keypress
var beforeVal = $field.val();
setTimeout(function() {
// this is the value after the keypress
var afterVal = $field.val();
$('#log').prepend(
$('<li></li>').text('value before: ' + beforeVal + '; value now: ' + afterVal)
);
}, 0);
});