Ultimate Vertical Center

ultimate_vertical_center.js

((store, render)=>{

store.htm = `
<div class="-cnt">
  <div class="-element">${store.content}</div>
</div>
<style>
#${store.id} .-cnt {
  background-color: #ededed;
  height: 75vw;
}
#${store.id} .-element {
   position: relative;
   top: 50%;
   -webkit-transform: translateY(-50%);
   -ms-transform: translateY(-50%);
   transform: translateY(-50%);
}
</style>
`;  

return render(store); 

})({id:"App", content: "Hello<br/>World"}, (store)=>{

const 
  cnt = document.getElementById(store.id) || 
    (()=>{
      var div = document.createElement("div");
      div.id = store.id;
      document.body.insertBefore(div, document.body.childNodes[0]);
      return div;
    })();
if (cnt.innerHTML !== store.htm) cnt.innerHTML = store.htm;

return "done.";  

});