AI solution for JavaScript Coding Question on BFE.dev
113. Virtual DOM I

Solution:

To solve this problem, we can define two functions virtualize and render. virtualize function will take a real DOM tree and return an object literal that represents the same tree structure. The render function will take this object literal presentation and recreate a DOM tree.

function virtualize(node) {  // Base case: if node is TextNode  if (node.nodeType === Node.TEXT_NODE) {    return node.textContent;  }  // Otherwise, create object for element node  const obj = {    type: node.nodeName.toLowerCase(),    props: {},    children: [],  };  // Add properties  for (const prop of node.attributes) {    obj.props[prop.name] = prop.value;  }  // Add children  for (const child of node.childNodes) {    obj.children.push(virtualize(child));  }  return obj;}function render(obj) {  // Base case: if obj is TextNode  if (typeof obj === "string") {    return document.createTextNode(obj);  }  // Create element node  const node = document.createElement(obj.type);  // Set properties  for (const prop in obj.props) {    node.setAttribute(prop, obj.props[prop]);  }  // Add children  for (const child of obj.children) {    node.appendChild(render(child));  }  return node;}

Let's test our solution:

// Create real DOM treeconst root = document.createElement("div");root.innerHTML = `  <h1> this is </h1>  <p class="paragraph">a <button>button</button> from <a href="https://bfe.dev"><b>BFE</b>.dev</a></p>`;// Virtualize DOM treeconst obj = virtualize(root);console.log(obj);/*{  type: 'div',  props: {},  children: [    {      type: 'h1',      props: {},      children: [' this is ']    },    {      type: 'p',      props: { class: 'paragraph' },      children: [        'a ',        {          type: 'button',          props: {},          children: ['button']        },        ' from ',        {          type: 'a',          props: { href: 'https://bfe.dev' },          children: [{ type: 'b', props: {}, children: ['BFE'] }, '.dev']        }      ]    }  ]}*/// Render object literal as DOM treeconst newRoot = render(obj);console.log(newRoot.outerHTML);/*<div>  <h1> this is </h1>  <p class="paragraph">a <button>button</button> from <a href="https://bfe.dev"><b>BFE</b>.dev</a></p></div>*/

As we can see from the console output, the virtualized object and the rendered DOM tree are the same as the original. Therefore, our solution works as expected.