【study】js去重到数据对象中的null值

 const arr = [
            {
                dateItem: [
                    { orderDate: 2, arrivalRule: 3, groupNum: 1, ruleType: 4, startDate: null },
                    { orderDate: 2, arrivalRule: 3, groupNum: 1, ruleType: 4, startDate: null },
                ],
                key: 1
            },
            {
                dateItem: [
                    { orderDate: null, arrivalRule: null, groupNum: undefined, ruleType: undefined, startDate: null }
                ],
                key: 2
            },
        ]
        
 // 想得到结果： arr= [
        //     {
        //         dateItem: [
        //              { orderDate: 2, arrivalRule: 3, groupNum: 1, ruleType: 4, startDate: null },
        //              { orderDate: 2, arrivalRule: 3, groupNum: 1, ruleType: 4, startDate: null },
        //         ],
        //         key: 1
        //     },
        // ]
        
        
   const handleArrivalList = arr2.filter((i) => {
            return i.dateItem.filter(j => {
                // if (j.orderDate || j.arrivalRule || j.startDate) {
                //     return true
                // } else {
                //     return false
                // }
                return j.orderDate || j.arrivalRule || j.startDate;
            }).length
        })