Array.prototype.repeat = function(){
  let shipObj = this.reduce((pre, cur)=>{
    pre[cur] ? pre[cur]++ : pre[cur] = 1;
    return pre;
  }, {})
  // console.log(arguments.length)
  // arguments
  let valList = Object.values(shipObj).sort((m,n)=>n-m);
  Object.keys(shipObj).forEach(key=>{
    valList.some((val,i)=>{
      if(shipObj[key] === val){
        valList[i] = [key, shipObj[key]];
        return true;
      }
      return false
    })
  })
  return valList;
}
var nn = ['Tiff', 'Alice', 'Tiff', 'Bruce', 'Alice', 'Bob'];
var res = nn.repeat()