Mastering one framework is not going to be enough. Make sure to hire a ReactJS developer who has expertise in working with a variety of different React-compatible technologies.
Continuous development and deployment have made it necessary for ReactJS developers to have a hands-on experience with widely used testing tools and frameworks.
If you want to track, organize and control changes over the codebase, it is absolutely necessary to hire a ReactJS developer with a stronghold over version control systems like Git.
A massive ecosystem such as React requires in-depth knowledge of React fundamentals & popular styling strategies.
State management is one of the biggest challenges, especially in complex applications. That's why you must hire a ReactJS developer who has experience working with ReactJS workflows.