统计字符串出现元素及出现次数

const S = "aabcccccaaa"
const arr1 = [...S]
let array = []
let obj = {}
  for(let i=0;i<arr1.length;i++){
    if(array.length>0){
      let item = array.find((item) =>
        item.name == arr1[i]
      )
      if(item === undefined){
        let newObj = {}
        newObj.name =  arr1[i]
        newObj.num = 1
        array.push(newObj)
      } else {
        item.num++
      }
    } else {
      obj.name = arr1[i]
      obj.num = 1
      array.push(obj)
    }
    return array // [{name: 'a',num: 5},{name: 'b',num: 1},{name: 'c',num: 5}]
  }