从嵌套对象生成HTML DOM

function createHTMLElement(tagName, attributes, children) {
  const element = document.createElement(tagName);

  if (attributes) {
    for (const [key, value] of Object.entries(attributes)) {
      element.setAttribute(key, value);
    }
  }

  if (children) {
    for (const child of children) {
      if (typeof child === 'string') {
        element.appendChild(document.createTextNode(child));
      } else {
        const { tagName, attributes, children } = child;
        element.appendChild(createHTMLElement(tagName, attributes, children));
      }
    }
  }

  return element;
}

const nestedObject = {
  tagName: 'div',
  attributes: { id: 'container' },
  children: [
    {
      tagName: 'h1',
      attributes: { class: 'title' },
      children: ['Hello, World!'],
    },
    {
      tagName: 'p',
      attributes: null,
      children: ['This is a paragraph.'],
    },
  ],
};

const htmlElement = createHTMLElement(
  nestedObject.tagName,
  nestedObject.attributes,
  nestedObject.children
);

document.body.appendChild(htmlElement);