js筛选出 字符串中出现频次最高的 字母

 var str = "dasdafdasftrdhsdgrfergasfsgjghkjgf"
   let sArr = str.split(‘‘);
   sArr = [...new Set(sArr)];
   let cArr = [];
   sArr.forEach(item => {
      let re = eval(`/${item}/ig`);
      let o = {s:item,count:0}
      o.count = str.match(re).length;
      cArr.push(o)
   })
   cArr.sort((a,b) => {
     return b.count - a.count;
   })
   let maxCount = cArr[0].count;
   let fArr = cArr.filter(item => {
     return item.count == maxCount;
   })
   console.log(fArr)