What's the best library in javaScript to create interface app?

Answer 1

If your app will be for desktop, use electronJS, case be for android or iOS, use the frameworks Ionic or React Native, case be only a web app use React, jQuery or the framework Angular

Answer 2

If you meaned desktop apps then... Visual studio code is very fast and responsive ide. It is written on Electronjs (https://electronjs.org). May be it will suit your needs.