I need to develop a front-end for a Android + iOS app. Looking for a language that supports cross-platform programming.

Easy to work with. Huge community support. Open Source. No unwanted updates.

Reactjs is much better with the server side rendering and virtual dom than Angular JS in multiple reasons. Reactjs has SEO-friendly and Angular JS is not despite being built by Google.

Community support

Huge community support for Reactjs. Hell lot of libraries. Use material UI for UI. Redux for state management. Everything is pretty much out of the box

Ease of learning

People say Reactjs js has steep learning curve. This is true for a web developer who does not know about classes. But if you already know about Classes it is much easier to work with ReactJS

on NPM

Best packager ever

Google Analytics is extremely easy to integrate. Works with google ads. JS based hence does not give double counts for request by same person. Gives more accurate analytics.