If you throw a ref-reference to a class component, the ref value will be an instance of the class. Is it possible to do something similar with a functional component — pass a ref and get, for example, a function declared inside the component?

In React functional components, you cannot directly get an instance like in class components because functional components do not have an instance of a class. However, you can use forwardRef together with useImperativeHandle to pass a ref and define which methods or properties will be accessible from outside.

Example:

import React, { useImperativeHandle, forwardRef, useRef } from 'react';

const MyComponent = forwardRef((props, ref) => {
  const localRef = useRef();

  useImperativeHandle(ref, () => ({
    myFunction: () => {
      console.log('Calling function from parent');
    }
  }));

  return <div ref={localRef}>Example component</div>;
});

// Usage:
// const ref = React.createRef();
// <MyComponent ref={ref} />
// ref.current.myFunction();

Thus, you can "expose" functions or data from a functional component via ref.