JSFiddle - React, Tailwind, and code Playground

HTML

<div contenteditable><p>editor</p></div><button onclick="document.execCommand('insertLineBreak', false, null); document.getElementsByTagName('div')[0].focus();">insertBreak</button>
<p id="log"></p>

JavaScript

var div = document.getElementsByTagName("div")[0];
div.addEventListener("input", ()=>{
  var children = "";
  var p = div.firstChild;
  for (var i = 0; i < p.childNodes.length; i++) {
    if (children != "") {
      children += ", ";
    }
    var child = p.childNodes.item(i);
    if (child.tagName) {
      children += child.tagName;
    } else {
      children += "text(" + child.data + ")";
    }
  }
  document.getElementById("log").textContent = children;
});