First of all, it depends on whether you want to learn native development or mixed development. Not to mention Native, there are several optional frameworks for mixed development, reactive native, ionic,

React Native still depends on Native. In addition to the official components, your team edition should be able to help you package your own native components. The front end alone is not enough. The main development is JS, and the highlight is that ES6, other JSX, Rex and so on can be used. Ionic is based on right angle, and multi-platform API is unified into JS interface.