reconciler.js

function reconcile(parentDom, instance, element) {
   /** code... */
  else if (instance.element.type === element.type) {
    // perform props update here
    updateDomProperties(instance.dom, instance.element.props, element.props);
    instance.childInstances = reconcileChildren(instance, element);
    instance.element = element;
    return instance;
  } 
     /** code... */
}

function instantiate(element) {
  const { type, props } = element;

  /** code... */
  const dom = isTextElement
    ? document.createTextNode("")
    : document.createElement(type);
   // apply new props and provide empty object as a prevObject since this is instanciation
  updateDomProperties(dom, {}, props);
   /** code... */
  
}