Understanding Fiber Architecture

Provide a conceptual example of Fiber nodes and how they enable incremental rendering of the component trees.
// Assume this is a simplified structure of a Fiber node
const fiberNode = {
    stateNode: null, // The component instance or DOM node
    child: null,      // The first child fiber
    sibling: null,   // The sibling fiber
    return: null     // The parent fiber
    // ... other properties

// Create a root Fiber node for our app
const rootFiber = Object.create(fiberNode);
rootFiber.stateNode = document.getElementById('app');

// Function to perform work on a fiber node
function performUnitOfWork(fiber) {
    // Simulate rendering by attaching children to the DOM
    if (fiber.child) {

    // Return the next unit of work
    if (fiber.child) {
        return fiber.child;
    } else {
        let nextFiber = fiber;
        while (nextFiber) {
            if (nextFiber.sibling) {
                return nextFiber.sibling;
            nextFiber = nextFiber.return;

// Represents a user-defined component that creates DOM nodes
function MyComponent() {
    // ... component logic

// Usage

// Create fiber nodes for our component tree
const myComponentFiber = Object.create(fiberNode);
myComponentFiber.stateNode = new MyComponent();

rootFiber.child = myComponentFiber;
myComponentFiber.return = rootFiber;
The code above represents a simplified model of the Fiber architecture in React. A Fiber node is created with certain properties representing the structure of the component tree. The 'performUnitOfWork' function simulates incremental rendering by recursively attaching child nodes to the DOM. The usage section showcases how a user-defined component might be integrated into the Fiber tree, and 'myComponentFiber' becomes a child of the root fiber, establishing a parent-child relationship.