JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" name="foo">
<a href="http://example.com/{value of foo}">Link</a>
JavaScript
$('[name=foo]').blur(function(){
var hrefVal = $(this).siblings("a").attr("href");
$('a').attr("href", hrefVal + $(this).val());
});