- It's in part inspired by React, but based on observables (like Knockout) instead of virtual dom.

- It is lightweight, has no dependencies, and takes only ~30KB minified.

- It needs no special tooling. It's nothing more than a library.

- It supports convenient DOM-building in JS, event dispatching, DOM event subscriptions, 9disposable components, and in-code CSS styling.

- It's fully typed for use with TypeScript.

- It's proven its worth by powering Grist's rich frontend app.

Source code: https://github.com/gristlabs/grainjs/