统计字符串里各个字符出现次数的算法

<script>
l=console.log
str='daaaaccbbb'

function statistics(str){
  frequency=[
    [1,str[0]]
  ]
  for(i=1;i<str.length;i++){
    fresh=true
    for(j=0;j<frequency.length;j++){
      if(str[i]==frequency[j][1]){
        frequency[j][0]++
        fresh=false
        break
      }
    }  
    fresh ? frequency.push([1,str[i]]) : ''
  }
  return frequency
}

rank=statistics(str).sort()


</script>