Function updateElement

code/composition/public/app.js:9161–9179

(returnFiber, current, element, expirationTime)

  }

  function updateElement(returnFiber, current, element, expirationTime) {
    if (current !== null && current.type === element.type) {
      // Move based on index
      var existing = useFiber(current, element.props, expirationTime);
      existing.ref = coerceRef(returnFiber, current, element);
      existing['return'] = returnFiber;
      {
        existing._debugSource = element._source;
        existing._debugOwner = element._owner;
      }
      return existing;
    } else {
      // Insert
      var created = createFiberFromElement(element, returnFiber.mode, expirationTime);
      created.ref = coerceRef(returnFiber, current, element);
      created['return'] = returnFiber;
      return created;
    }
  }

  function updatePortal(returnFiber, current, portal, expirationTime) {
    if (current === null || current.tag !== HostPortal || current.stateNode.containerInfo !== portal.containerInfo || current.stateNode.implementation !== portal.implementation) {