How to replace <li> tag in HTML with another tag and place it value in the new tag

I need to update the following HTML to wrap each <li> with <li><li-text>{li value}</li-text>

<ul><li>one</li><li>two<ul><li>three<ul><li>four<ul><li>five</li></ul></li></ul></li></ul></li></ul>

hints: I ONLY USING JS, NO JQUERY

I'm trying this, but it's not working as expected!

var html = `<ul><li>one</li><li>two<ul><li>three<ul><li>four<ul><li>five</li></ul></li></ul></li></ul></li></ul>`.replace(/<li[^>]*>/g,'<li><li-text>$&</li-text>')

The result I'm getting is not correct! the value of list should be between <li-text></li-text> tags!

<ul><li><li-text><li></li-text>one</li><li><li-text><li></li-text>two<ul><li><li-text><li></li-text>three<ul><li><li-text><li></li-text>four<ul><li><li-text><li></li-text>five</li></ul></li></ul></li></ul></li></ul>

Forget about parsing HTML yourself. You can use the browser's built-in parser, select your li elements, and replace the content to be wrapped with li-text.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

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)

<!-- end snippet -->

Parse the content as HTML, select all <li> elements, then replace each direct-children text node with a wrapper:

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;
}

Try it:

<!-- begin snippet: js hide: true -->

<!-- language: lang-js -->

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))
);

<!-- language: lang-html -->

<script src="https://gh-canon.github.io/stack-snippet-console/console.min.js"></script>

<!-- end snippet -->