text: function solution(a) {
      const numsMap = {};    
      const str = String(a.join(''));
      
      for (let i = 0; i < str.length; i++){
          const num = str[i];
          if (num in numsMap) numsMap[num]++;
          else numsMap[num] = 1;  
      }   
      
      let result = [];
      let maxnums = -Infinity;
      for (let nums in numsMap) {        
          if (maxnums < numsMap[nums]) maxnums = numsMap[nums];        
      }
      
      for (let nums in numsMap) {        
          if (numsMap[nums] === maxnums) result.push(Number(nums));        
      }    
      return result;
  }