With the introduction of the wordpress REST API we can start doing all sorts of neat things by pulling data into the frontend using javascript. One such thing is to build an entire theme as a single-page application where the user never has to refresh the page. Instead of going to new pages with new requests, you just dynamically populate the page with the appropriate content for the user.
React.js is a javascript library for building these dynamically populated templates on a page. This talk is an overview of how to use react.js to grab data from the REST api and render it dynamically on the frontend.