gistfile1.txt

function filterLists(list){
    try{
      let filteredList=list.filter(function(item, index){
        return item.age >= 30 && item.age <= 40
      });
      let genderIndex=[]
      let groupedList=filteredList.reduce(function(accum, item, index){
        let gIndex= genderIndex.indexOf(item.gender);
        if(gIndex>=0){
          accum[gIndex].push(item);
          return accum;          
        }
        else{
          genderIndex.push(item.gender)
          accum.push([item]);
          return accum;
        }        
      },[]);
      return groupedList
    }
    catch(e){
      return "List must be an array of Object";
    }
}