inline_wrapper.js

function fixhtml(html) {
  var div, dom, hasBlockChild, needWrapping, textOrInlineChildren, treeWalker;
  dom = document.createElement('div');
  html = html.replace(/\s+/g, " ").replace(/> </g, "><"); // removes white space
  while (html.match(/<(h[1-5]|p|strong|div|u|em|a|bi) ?[^>]*>\s?<\/\1>/g)) {
    html = html.replace(/<(h[1-5]|p|strong|div|u|em|a|b|i) ?[^>]*>\s?<\/\1>/g, ""); //removes empty tags recursively, except iframes
  }
  dom.innerHTML = html;
  Array.from(dom.querySelectorAll("h1 h1")).forEach(function(node) {
    return node.outerHTML = node.innerHTML; //unwrap nested h1's
  });
  needWrapping = [];
  // walk dom, get all block node
  treeWalker = document.createTreeWalker(dom, NodeFilter.SHOW_ELEMENT, {
    acceptNode: (node) => {
      if (BLOCK_TAGS[node.nodeName.toLowerCase()] != null) {
        return NodeFilter.FILTER_ACCEPT;
      } else {
        return NodeFilter.FILTER_SKIP;
      }
    }
  });
  
  // get all node need wrapping
  while (treeWalker.nextNode()) {
    div = treeWalker.currentNode;
    hasBlockChild = Array.from(div.childNodes).find((node) => {
      return BLOCK_TAGS[node.nodeName.toLowerCase()] != null;
    });
    if (hasBlockChild) {
      textOrInlineChildren = Array.from(div.childNodes).filter((node) => {
        return BLOCK_TAGS[node.nodeName.toLowerCase()] == null;
      });
      needWrapping.push(...textOrInlineChildren);
    }
  }
  
  // wrap all nodes
  needWrapping.forEach((tn) => {
    var wrapper;
    if (tn.textContent.length === 0) { // remove empty inline tags
      return tn.remove();
    }
    wrapper = document.createElement('div');
    wrapper.className = "inlinewrapper";
    tn.parentNode.replaceChild(wrapper, tn);
    return wrapper.appendChild(tn);
  });
  return dom.innerHTML.replace(/\s+/g, " ").replace(/> </g, "><").replace(/(<input[^>]+)(>)/g, "$1 /$2");
};