TL;DR; A custom renderer for ReactJS that uses Web Workers to run the expensive Virtual DOM diffing calculations

Tl;Dr; ReactJS is faster when Virtual DOM reconciliations are done on a Web Worker thread.

React is fast, thanks to the VirtualDOM. Using a diffing algorithm, the browser DOM nodes are manipulated only when there is a state change. This algorithm is computationally expensive. Using webworkers to perform the calculations can make React even faster.