找出指定字符串中重复最多的字符

function test(str){
      let _length = 0;
      let result = [];
      let str_list = str.split('');
      let _result = new Set(str_list);
      for (let w of _result) {
         let number = str_list.filter(element => element === w).length;
         if (number > _length) {
            result = [
               {
                  _length: number,
                  word: w
               }
            ];
            _length = number;
         } else if (number === _length) {
            result.push({
               _length: number,
               word: w
            });
         }
      }
      return result
}

 test("a eh sjdh s d");//[{_length: 2, word: "h"},{_length: 2, word: "s"},{_length: 2, word: "d"}]