忘记自己解析HTML。您可以使用浏览器的内置解析器，选择您的li元素，并使用li-text替换要 Package 的内容。

const input = `<ul><li>one</li><li>two<ul><li>three<ul><li>four<ul><li>five</li></ul></li></ul></li></ul></li></ul>`

const parser = new DOMParser()
const doc = parser.parseFromString(input, "text/html")
doc.querySelectorAll("li").forEach(li => li.innerHTML = `<li-text>${li.innerHTML}</li-text>`)

const output = doc.body.innerHTML
console.log(output)

将内容解析为HTML，选择所有<li>元素，然后用 Package 器替换每个直接子文本节点：

function addWrapperToLi(html) {
  const parser = new DOMParser();
  const parsed = parser.parseFromString(html, 'text/html');

  const textNodes = [...parsed.querySelectorAll('li')].flatMap(
    // .childNodes contains all kinds of nodes, including elements
    element => [...element.childNodes].filter(
      // ...but we only want text nodes.
      node => node.nodeType === Node.TEXT_NODE
    )
  );

  textNodes.forEach(node => {
    const wrapper = document.createElement('li-text');
    wrapper.innerText = node.textContent;
    node.parentElement.replaceChild(wrapper, node);
  });

  return parsed.body.innerHTML;
}

试试看：

console.config({ maximize: true });

function addWrapperToLi(html) {
  const parser = new DOMParser();
  const parsed = parser.parseFromString(html, 'text/html');

  const textNodes = [...parsed.querySelectorAll('li')].flatMap(
    element => [...element.childNodes].filter(
      node => node.nodeType === Node.TEXT_NODE
    )
  );

  textNodes.forEach(node => {
    const wrapper = document.createElement('li-text');
    wrapper.innerText = node.textContent;
    node.parentElement.replaceChild(wrapper, node);
  });

  return parsed.body.innerHTML;
}

const testcases = [
  '<ul><li>one</li><li>two<ul><li>three<ul><li>four<ul><li>five</li></ul></li></ul></li></ul></li></ul>',
  '<ul><li>one</li><li>two<ul><li>three<ul><li>four<ul><li>five</li></ul>after four</li></ul></li></ul>after two</li></ul>'
];

testcases.forEach(
  testcase => console.log(addWrapperToLi(testcase))
);

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