过滤具有小于和当前日期的对象数组答案

【问题标题】：filter array of objects with less than and present date过滤具有小于和当前日期的对象数组
【发布时间】：2021-10-01 07:07:33
【问题描述】：

我有不同日期的对象。我如何过滤掉过去的日期和现在的日期。我有过去和未来的日期，我只想要对象的过去日期和当前日期。我尝试过滤，但我不确定我在做什么错我的代码：

const arr = [{
    "id": "e18dae03-99c7-4ffa-be2f-a595fc7fad15",
    "event_date": "2021-09-30T01:00:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
},
{
    "id": "e18dae03-99c7-4ffa-be2f-a595fc7fad15",
    "event_date": "2021-10-30T01:00:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
}
{
    "id": "765a508f-fb47-4de4-bf69-19f0db38ccfc",
    "event_date": "2021-09-17T22:03:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
},
{
    "id": "bc07a114-43f4-49a1-bb6c-fec801aee749",
    "longitude": null,
    "event_date": "2021-11-19T07:51:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
}
]


const filterByExpiration = () => arr.filter(({ event_date }) => event_date <= new Date());

【问题讨论】：

标签： javascript arrays reactjs object

【解决方案1】：

event_date 是一个字符串。您应该先将其转换为 Date 对象。

const filterByExpiration = () => arr.filter(({ event_date }) => new Date(event_date) <= new Date());

或将其与 ISO 日期字符串进行比较

const filterByExpiration = () => arr.filter(({ event_date }) => event_date <= new Date().toISOString());

【讨论】：

【解决方案2】：

字符串不能与日期进行比较。您需要使用new Date(event_date) 将event_date 解析为Date。正确的比较是

new Date(event_date) <= new Date()

const arr = [{
        "id": "e18dae03-99c7-4ffa-be2f-a595fc7fad15",
        "event_date": "2021-09-30T01:00:00.000Z",
        "alert_name": null,
        "alert_level": null,
        "alert_action": null,
        "alert_details": null,
    },
    {
        "id": "e18dae03-99c7-4ffa-be2f-a595fc7fad15",
        "event_date": "2021-10-30T01:00:00.000Z",
        "alert_name": null,
        "alert_level": null,
        "alert_action": null,
        "alert_details": null,
    },
    {
        "id": "765a508f-fb47-4de4-bf69-19f0db38ccfc",
        "event_date": "2021-09-17T22:03:00.000Z",
        "alert_name": null,
        "alert_level": null,
        "alert_action": null,
        "alert_details": null,
    },
    {
        "id": "bc07a114-43f4-49a1-bb6c-fec801aee749",
        "longitude": null,
        "event_date": "2021-11-19T07:51:00.000Z",
        "alert_name": null,
        "alert_level": null,
        "alert_action": null,
        "alert_details": null,
    }
]


const filterByExpiration = () => arr.filter(({ event_date }) => new Date(event_date) <= new Date());

console.log(filterByExpiration());

【讨论】：

【解决方案3】：

您的event_date 是一个字符串。这就是为什么比较会给出你不期望的结果。您需要将字符串转换为Date object。

const arr = [{
    "id": "e18dae03-99c7-4ffa-be2f-a595fc7fad15",
    "event_date": "2021-09-30T01:00:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
},
{
    "id": "e18dae03-99c7-4ffa-be2f-a595fc7fad15",
    "event_date": "2021-10-30T01:00:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
},
{
    "id": "765a508f-fb47-4de4-bf69-19f0db38ccfc",
    "event_date": "2021-09-17T22:03:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
},
{
    "id": "bc07a114-43f4-49a1-bb6c-fec801aee749",
    "longitude": null,
    "event_date": "2021-11-19T07:51:00.000Z",
    "alert_name": null,
    "alert_level": null,
    "alert_action": null,
    "alert_details": null,
}
]


const filterByExpiration = () => arr.filter(({ event_date }) => {
let x = new Date(event_date);
return (x <= new Date());
});

console.log(filterByExpiration());

【讨论】：

【解决方案4】：

您必须将arr 的每个节点中的节点event_date 转换为日期对象才能进行比较。截至目前，它是一个字符串。

您还必须调用filterByExpiration 函数。你刚刚定义了它，它还没有被调用。

工作小提琴

const arr = [{"id":"e18dae03-99c7-4ffa-be2f-a595fc7fad15","event_date":"2021-09-30T01:00:00.000Z","alert_name":null,"alert_level":null,"alert_action":null,"alert_details":null},{"id":"e18dae03-99c7-4ffa-be2f-a595fc7fad15","event_date":"2021-10-30T01:00:00.000Z","alert_name":null,"alert_level":null,"alert_action":null,"alert_details":null},{"id":"765a508f-fb47-4de4-bf69-19f0db38ccfc","event_date":"2021-09-17T22:03:00.000Z","alert_name":null,"alert_level":null,"alert_action":null,"alert_details":null},{"id":"bc07a114-43f4-49a1-bb6c-fec801aee749","longitude":null,"event_date":"2021-11-19T07:51:00.000Z","alert_name":null,"alert_level":null,"alert_action":null,"alert_details":null}];
const filterByExpiration = () => arr.filter(({ event_date }) => new Date(event_date) <= new Date());
console.log(filterByExpiration())

【讨论】：