If you're extending some class you need to make sure the parent class is properly initialized before your class. This is OOP, not just React/JS. A few things to keep in mind:
- if you don't need to do anything in the constructor of your component, you can omit it and a default one will be used. You don't need to do anything.
- if you do anything in the constructor of your component, then the first thing inside your constructor should be the call to super(props)