删除排序数组中的重复项

function removeDuplicates(nums) {
    let obj = {}
    for(let i = nums.length-1;i > -1;i-- ){
        let item = nums[i]
        if(obj[item]){
            obj[item] += 1
            if(obj[item] > 2){
                nums.splice(i,1)
            }
        }else{
            obj[item] = 1
        }
    }
    return nums.length
}