It is a bit more complicated in practice though than "a React component is just a function that rerenders when called". In some ways, the function acts more like a class, and then React, internally, uses it to create "instances" of components that have their own set of data stored. (Which is why hooks like useState, useRef, etc. can work - because data is being stored internally in React tied to a component instance.)
It _is_ true that when you call a React function component it "runs its code" just like any regular old JS function. But when that function gets run and what all the side effects of its code are actually is quite complex.
It _is_ true that when you call a React function component it "runs its code" just like any regular old JS function. But when that function gets run and what all the side effects of its code are actually is quite complex.