The "URL router" in my current project begins with "onhashchange = function () {" and is essentially a five line conditional. It might grow to ten lines. All it

The "URL router" in my current project begins with "onhashchange = function () {" and is essentially a five line conditional. It might grow to ten lines. All it does is set the root props based on query parameters. Not rocket science. I'm using Fetch.js and a Promise polyfill in order to do AJAX stuff (the native XHR API is a bit tedious). But basically the answer is: yes, you can! You can even write an SPA using nothing but the regular W3C APIs! React just makes it very easy to keep the DOM in sync with your application state.