Перенос строки через JavaScript

let chat = document.getElementById("chat"); 
 
setInterval(e => { 
  addMessage(Math.random().toString(36).substring(2)); 
  chat.childNodes.length >= 5 && removeFirstMessage(); 
}, 1000) 
 
function addMessage(newMsg) { 
  let block = document.createElement('div'); 
  block.classList.add('block'); 
  block.style.backgroundColor = `hsl(${Math.random()*360},55%,85%)`; 
  block.textContent = newMsg; 
  setTimeout(e => block.style.opacity = 1); 
  chat.append(block); 
} 
 
function removeFirstMessage() { 
  chat.firstChild.style.opacity = 0; 
  let h = chat.firstChild.getBoundingClientRect().height; 
  chat.firstChild.style.marginTop = `-${h + 5}px`; // 5 - margin 
  setTimeout(e => chat.firstChild.remove(), 500); 
}

.block { 
  width: 300px; 
  margin-bottom: 5px; 
  padding: 5px; 
  border-radius: 5px; 
  opacity: 0; 
  transition: 300ms; 
}

<div id="chat"></div>