const funcA = сompose(funcB, funcC, funcD);

const funcA = ()=> {
  funcB( funcC( funcD() ) ) ;
};

function funcA() {
  function funcB() {
      function funcC() {
         function funcD()
      }
  }
}

<button onclick="customAction()" /> // html
<input v-focus v-my-directive="someValue" /> // vue

switсh (condition) {
  case stateA: actionA();
  case stateB: actionB();
  case stateC: actionC();
}

function MyComponent() {
  const jsxContent = (<div/>);
  console.log(jsxContent);
  return jsxContent;
}

const rootElement = document.getElementById('root');
ReactDOM.render(<App />, rootElement);
console.log(rootElement._reactRootContainer._internalRoot);

import { useState, useContext, useEffect,useMemo, useCallback,
         useRef, createContext } from 'react';
import ReactDOM from 'react-dom';
const ContextExample = createContext('');
function ChildComponent() {
  useState('childComponentValue');
  return <div />;
}
function useMyHook() {
  return useState('valueB');
}
function ParentComponent() {
  const [valueA, setValueA] = useState('valueA');
  useEffect(function myEffect() {}, [valueA]);
  useMemo(() => 'memoized ' + valueA, [valueA]);
  useCallback(function myCallback() {}, [valueA]);
  useRef('refValue');
  useContext(ContextExample);
  useMyHook();
  const jsxContent = (
    <div>
      <ChildComponent />
      <button onClick={() => setValueA('valueA new')}>Update valueA</button>
    </div>
  );
  console.log('component under the hood: ', jsxContent);
  return jsxContent;
}
const rootElement = document.getElementById('root');
ReactDOM.render(
  <ContextExample.Provider value={'contextValue'}>
    <ParentComponent />
  </ContextExample.Provider>,
  rootElement,
);