Ionic uses WebView
Phonegap uses WebView
Ionic Native uses WebView for UI + Wrapper around Curated set of Cordova Plugins for Native Access
Nativescript uses V8 JS Runtime for running JS and use JS mappings to Native API to make Native Calls. It also uses XML to define UI Templates which at runtime are rendered as Native UI Components
React Native, like Nativescript, uses JS Runtime but for UI, it’s better as it uses JSX to declare UI Templates and these are then mapped to their native UI Counterparts for Native UI rendering
In React, a component describes its own appearance; React then handles the rendering for you. A clean abstraction layer separates these two functions. In order to render components for the web, React uses standard HTML tags. This same abstraction layer, known as the “bridge,” enables React Native to invoke the actual rendering APIs on iOS and Android. On iOS, that means that your React Native components render to real UI Views, while on Android, they’ll render to native Views.