TaskPlanner

function solution(arr){
  let dailyTask = arr.shift().split(' ').map(Number);
  arr.forEach(function(element){
      if(element === 'End'){
        return;
      }
      let token = element.split(' ');
      let command = token.shift();
      switch(command){
          case 'Complete':
               let ind = +token[0];
               if(ind < 0 || ind >= dailyTask.length){
                   break;
               }
               if(dailyTask.includes(ind)){
                  dailyTask.splice(ind,1,0);
               }
               ;break;
          case 'Change':
               let index = +token[0];
               let tim = +token[1];
               if(index < 0 || index >= index.length){
                  break;
               }
               if(dailyTask.includes(index)){
                   dailyTask.splice(index,1,tim);
               }
               ;break;
          case 'Drop':
               let drop = +token[0];
               if(drop < 0 || drop >= drop.length){
                break;
               }
               if(dailyTask.includes(drop)){
                   dailyTask.splice(drop,1,-1);
               }
               ;break;
          case 'Count':
               switch(token[0]){
                   case 'Completed':
                        let counter = 0;
                        for(let completed of dailyTask){
                           if(completed === 0){
                            counter++
                           }

                        }
                        console.log(counter)
                         ;break;
                   case 'Incomplete':
                         let sumIncomplete = 0;
                         for(let incomplete of dailyTask){
                             if(incomplete > 0){
                                 sumIncomplete += incomplete;
                             }
                         }
                         console.log(sumIncomplete)
                         ;break;
                   case 'Dropped':
                        let sumDropped = 0;
                        for(let dropped of dailyTask){
                            if(dropped < 0){
                                sumDropped += dropped;
                            }
                        }
                        console.log(Math.abs(sumDropped));
                        ;break;
               }
               ;break;

      }
  })
  let incompleteTask = [];
  for(let incompl of dailyTask){
      if(incompl > 0){
        incompleteTask.push(incompl)
      }
  }
  console.log(incompleteTask.join(' '))
}
solution([
// '1 -1 2 3 4 5',
// 'Complete 4',
// 'Change 0 4',
// 'Drop 3',
// 'Count Dropped',
// 'End'

'1 2 3 4 5 4 0 3 2 1',
'Complete 0',
'Complete 1',
'Complete 2',
'Drop 3',
'Change 4 1',
'Count Completed',
'End',

])