2023-11-23

  数组对象判断某个值出现的次数

例如：

let  areaArr = [{areaId:1,areaName:'区域1'}，{areaId:2,areaName:'区域2'}，{areaId:1,areaName:'区域1'}]

//获取需要判断的属性

const titleList = areaArr.map(item => {

        return item.areaId

      })

getRepeatNum (titleList) {

      return titleList.reduce((prev, next) => {

        prev[next] = (prev[next] + 1) || 1

        return prev

      }, {})

    },

console.log(this.getRepeatNum(titleList)) //{1: 2,2,1}