选日期的时候提取相邻的日期天数？

Question

checkList:[                    {                        date:'2019-01-01',                        num:1,                        roomId:1                    },                    {                        date:'2019-01-02',                        num:1,                        roomId:1                    },                    {                        date:'2019-01-03',                        num:1,                        roomId:1                    },                    {                        date:'2019-01-05',                        num:1,                        roomId:1                    },                    {                        date:'2019-01-03',                        num:1,                        roomId:2                    },                    {                        date:'2019-01-04',                        num:1,                        roomId:2                    }                ],                checkList2:[                    {                        date:'2019-01-01',                        num:3,                        roomId:1                    },                    {                        date:'2019-01-05',                        num:1,                        roomId:1                    },                    {                        date:'2019-01-03',                        num:2,                        roomId:2                    }                ]最终我想把list这个初始数据变成list2这样的数据要怎么弄，num是天数，roomId是房间id