如何在 JavaScript 中过滤和 map 阵列

Question

原始数组中有几个对象，每个对象都有三个属性（时间戳、名称和年龄）。

如果连续多个时间戳相隔 15 分钟，它们将被分组到同一个 object 中。 之后，将添加一个名为 end 的新属性，该属性将是该组的最后一个元素的时间戳值加上 15 分钟。

如果一行中没有多个元素之间相差 15 分钟，则 end 属性将时间戳加上 15 分钟作为值。

这是我当前的代码：

 const data = [ { timestamp: '2021-11-23T14:15:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T14:30:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T14:45:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T15:45:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T14:15:00+0000', name: 'Anne', age: 32, }, { timestamp: '2021-11-23T14:30:00+0000', name: 'Anne', age: 32, }, { timestamp: '2021-11-23T14:45:00+0000', name: 'Anne', age: 32, }, { timestamp: '2021-11-23T15:45:00+0000', name: 'Anne', age: 32, }, ] const newArray = data.reduce((accumulator, current) => { const end = new Date(Date.parse(current.timestamp) + 15 * 60 * 1000) if (accumulator.length === 0) { accumulator.push({...current, end, }) } else { const last = accumulator[accumulator.length - 1] if (last.name === current.name && last.age === current.age) { last.end = end } else { accumulator.push({...current, end, }) } } return accumulator }, []) console.log(newArray)

然而，我的代码的最终结果并不是我想要的。 我希望我的结果是这样的：

[
    {
        timestamp: '2021-11-23T14:15:00+0000',
        name: 'John',
        age: 25,
        end: '2021-11-23T15:00:00+0000'
    },
    {
        timestamp: '2021-11-23T15:45:00+0000',
        name: 'John',
        age: 25,
        end: '2021-11-23T16:00:00+0000'
    },
    {
        timestamp: '2021-11-23T14:15:00+0000',
        name: 'Anne',
        age: 32,
        end: '2021-11-23T15:00:00+0000'
    },
    {
        timestamp: '2021-11-23T15:45:00+0000',
        name: 'Anne',
        age: 32,
        end: '2021-11-23T16:00:00+0000'
    }
]

Answer 1

如果找到，您可以搜索最后一个间隔并更新end 。 否则添加一个新的 object。

 const data = [{ timestamp: '2021-11-23T14:15:00+0000', name: 'John', age: 25 }, { timestamp: '2021-11-23T14:30:00+0000', name: 'John', age: 25 }, { timestamp: '2021-11-23T14:45:00+0000', name: 'John', age: 25 }, { timestamp: '2021-11-23T15:45:00+0000', name: 'John', age: 25 }, { timestamp: '2021-11-23T14:15:00+0000', name: 'Anne', age: 32 }, { timestamp: '2021-11-23T14:30:00+0000', name: 'Anne', age: 32 }, { timestamp: '2021-11-23T14:45:00+0000', name: 'Anne', age: 32 }, { timestamp: '2021-11-23T15:45:00+0000', name: 'Anne', age: 32 }] const newArray = data.reduce((accumulator, current) => { const end = new Date(Date.parse(current.timestamp) + 15 * 60 * 1000).toISOString(), item = accumulator.find(o => o.name === current.name && o.end === new Date(current.timestamp).toISOString() ); if (item) item.end = end; else accumulator.push({...current, end }); return accumulator; }, []) console.log(newArray);

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Answer 2

您可以使用Array.reduce()来获得所需的结果，就像在您自己的代码中一样，但我们可以稍作更改以更新累加器数组中的 lastItem，如果

• 名称相同（lastItem.name === name）
• 日期在 15 分钟内

如果不满足这个条件，我们只需添加到累加器数组中。

 const data = [ { timestamp: '2021-11-23T14:15:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T14:30:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T14:45:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T15:45:00+0000', name: 'John', age: 25, }, { timestamp: '2021-11-23T14:15:00+0000', name: 'Anne', age: 32, }, { timestamp: '2021-11-23T14:30:00+0000', name: 'Anne', age: 32, }, { timestamp: '2021-11-23T14:45:00+0000', name: 'Anne', age: 32, }, { timestamp: '2021-11-23T15:45:00+0000', name: 'Anne', age: 32, }, ] const result = data.reduce((acc, { timestamp, name, age }) => { let lastItem = acc[acc.length - 1]; let end = new Date(Date.parse(timestamp) + 15*60*1000); // If the current row matches just update the end time if (lastItem && lastItem.name === name && (Date.parse(lastItem.end) - Date.parse(timestamp) >= 0)) { lastItem.end = end; } else { acc.push({ timestamp, name, age, end }); } return acc; }, []) console.log(result)

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