Question

我有一个数组，其中每10秒包含一个特定值的快照：

arr = [
 {snapshotAt: "2019-08-20T18:23:46.3915797-07:00", amount: 5233123},
 {snapshotAt: "2019-08-20T18:23:56.4835221-07:00", amount: 5233221},
 ...
 {snapshotAt: "2019-08-21T10:54:38.9182797-07:00", amount: 5594822},
 {snapshotAt: "2019-08-21T10:54:48.3915817-07:00", amount: 5595115},
 {snapshotAt: "2019-08-21T10:54:58.1827367-07:00", amount: 5595350},
]

我需要每分钟获取最大金额：

reducedSnapshot: [
{snapshotAt: "2019-08-20T18:23:00-07:00", amount: 5593221},
...
{snapshotAt: "2019-08-21T10:54:00-07:00", amount: 5595350},
]

Answer 1

到目前为止，我有这个。它似乎正在工作。我还没有测试边缘情况：

arr = [
    {snapshotAt: new Date("2019-08-20T18:23:46.3915797-07:00"), amount: 5233123},
    {snapshotAt: new Date("2019-08-20T18:23:56.4835221-07:00"), amount: 5233221},
    {snapshotAt: new Date("2019-08-21T10:54:38.9182797-07:00"), amount: 5594822},
    {snapshotAt: new Date("2019-08-21T10:54:48.3915817-07:00"), amount: 5595115},
    {snapshotAt: new Date("2019-08-21T10:54:58.1827367-07:00"), amount: 5595350},
];


function groupBy(snapshots) {
    let map = new Map(); 
    snapshots.forEach(snapshot => {
        let key = `${snapshot.snapshotAt.getFullYear()}-${snapshot.snapshotAt.getMonth()+1}-${snapshot.snapshotAt.getDate()} ${snapshot.snapshotAt.getHours()}:${snapshot.snapshotAt.getMinutes()}`;
        let val = map.get(key);
        if(!val){ 
            map.set(key, {snapshotAt: new Date(key), amount: snapshot.amount }); 
        }
        else{
            val.amount = (snapshot.amount > val.amount)? snapshot.amount : val.amount; 
        }
    });
    return Array.from(map.values()); 
}

console.log(groupBy(arr)); 

output: 
[ { snapshotAt: 2019-08-21T01:23:00.000Z, amount: 5233221 },
  { snapshotAt: 2019-08-21T17:54:00.000Z, amount: 5595350 } ]

打字稿：如何按分钟分组？

1 个答案: