How do you define a professional ReactJS developer

I want to know your insights on defining a professional ReactJS developer.

Comments

[Andreas Sander]

1. Knows the JavaScript fundamentals
2. Knows the newest changes in the React ecosystem
3. Has done React-based projects in previous jobs
4. Can trade-off between different decisions necessary to be done while designing the React component composition (e.g., context vs. redux/mobx vs. passing props).

[Aftab Syed]

Only when you have written about 5 complete applications in ReactJS.