inferno

Inferno is a JavaScript library for building user interfaces that takes the same overall design ideas as React — components, one-way data flow, JSX templates, a familiar component lifecycle — and reimplements them with raw runtime speed as the headline goal. The maintainers explicitly position it as a React-like option for cases where rendering performance matters most, such as real-time data dashboards or pages with very large DOM trees.

Under the hood Inferno still works through a virtual DOM (an in-memory description of what the page should look like), but it bakes in a number of tricks to make updates cheap. Its own JSX compilers, available as plugins for Babel, TypeScript and SWC, turn your component code into specialised "createVNode" calls instead of generic ones, so the engine can take shortcuts at runtime. The diffing process uses bitwise flags to remember the shape of objects, and child nodes are only normalised when absolutely necessary. On top of that the library adds features that React does not have out of the box, like lifecycle events on functional components, controlled form elements, portals, fragments, refs and special animation callbacks. There is also an isomorphic server-side rendering package called inferno-server.

You would reach for Inferno when you want the familiar React mental model but cannot afford React's runtime cost, for example on slow devices, in embedded web views, or on pages where a small change must repaint a huge tree without dropping frames. It runs in modern browsers without polyfills, is MIT-licensed, and ships as an npm package. The full README is longer than what was provided.