baranovxyz

const factorial = trampoline(function _factorial(n, acc = 1) {
  if (n <= 1) return acc;
  return () => _factorial(n - 1, n * acc);
});

console.log(factorial(5));

baranovxyz

function trampoline(f) {
  return function trampolined(...args) {
    let result = f.bind(null, ...args);

    while (typeof result === 'function') result = result();

    return result;
  };
}

baranovxyz

function traverseDOM(tree) {
  if (isLeaf(tree)) tree.className = 'leaf';
  else for (const leaf of tree.childNodes) traverseDOM(leaf);
}

baranovxyz

function recursiveFn(n) {
  if (n < 0) return true;
  recursiveFn(n - 1);
}

recursiveFn(100000); // RangeError: Maximum call stack size exceeded

baranovxyz

function factorial(n) {
  if (n <= 1) return 1;
  return n * factorial(n - 1);
}

console.log(factorial(5)); // 120

baranovxyz

const Modal = ({children}) => <div className='Modal'>
    {children}
</div>;

baranovxyz

const App = () => {
  const [showModal, setShowModal] = useState(false);
  const handleKeyup = e => e.keyCode === 27 && setShowModal(false);
  const toggleModal = () => setShowModal(!showModal);
  useEffect(() => {
    if (showModal) window.addEventListener('keyup', handleKeyup);
    return () => window.removeEventListener('keyup', handleKeyup);
  });
  
  return <div onClick={toggleModal} className="App">

baranovxyz

.Modal {
  /* fixed position will always show modal in the top left corner */
  position: fixed;
  top: 0;
  left: 0;
  /* z-index to show modal even if it is used before some other elements */
  z-index: 5;
  /* make modal fill whole window */
  width: 100vw;
  height: 100vh;

baranovxyz

for (const el of array) {
  // do something here
}

baranovxyz

Array.prototype.forEach(el => {
  // do something here
});