Calypso is a modern shell for the old WordPress back end, using the soon to be available REST API. The shell is built with contemporary technologies such as React and Node.js. The interface is built off a clean slate and is already in production use over at WordPress.com.
Decoupling Drupal and working with a front end framework has been a hot topic in the Drupal Community for a while now. Dries Buytaert has discussed the prospects of different options, and has even credited the Angular 2 team for changing their licensing to be compatible with Drupal.
– Drupal team working on Angular 2 Universal support for Twig / PHP
These are competing technologies and the battle has now been upped a notch. What remains notable is that both sit on the shoulders of Giants; WordPress Facebook’s and Drupal on Google’s. The odd one out is Laravel showing support for Vue.js:
– The Vast World of Vue.js 0.12
JS Comparison: Angular vs. React vs. Vue