index.html

<div id="root"></div>

mesterum

function permAlone(str) {
  if(str=='') return 1
  const bag=new Map()
  for(const c of str){
    bag.set(c,(bag.get(c)||0)+1)
  }
  const essence=[]
  for(let v of bag.values()){
    essence[--v]=(essence[v]||0)+1
  }