根据两个条件减少javascript中的数组[关闭]

Posted 2023-02-16

【中文标题】根据两个条件减少javascript中的数组[关闭]

【英文标题】：Reduce array in javascript based on two conditions [closed]

【发布时间】：2022-01-06 06:05:04

【问题描述】：

假设我们有一个对象数组，例如：

[ 
     id: 1, time: "2021-05-02 10:12:45.123" ,
     id: 1, time: "2021-05-02 11:12:45.123" ,
     id: 1, time: "2021-05-02 12:12:45.123" ,
     id: 2, time: "2021-05-02 05:12:45.123" ,
     id: 1, time: "2021-05-01 12:12:45.123" ,
     id: 2, time: "2021-05-01 05:12:45.123" ,
     id: 2, time: "2021-05-01 04:12:45.123" ,
     id: 3, time: "2021-05-01 10:12:45.123" ,
]

所以我的目的是减少 javascript 中的数组，因此结果是 -> 每天的每个 Id 都有最新的时间，例如：

[ 
     id: 1, time: "2021-05-02 12:12:45.123" ,
     id: 2, time: "2021-05-02 05:12:45.123" ,
     id: 1, time: "2021-05-01 12:12:45.123" ,
     id: 2, time: "2021-05-01 05:12:45.123" ,
     id: 3, time: "2021-05-01 10:12:45.123" ,
]

请你帮忙。提前致谢

【参考方案1】：

您可以使用reduce轻松实现结果

const arr = [
   id: 1, time: "2021-05-02 10:12:45.123" ,
   id: 1, time: "2021-05-02 11:12:45.123" ,
   id: 1, time: "2021-05-02 12:12:45.123" ,
   id: 2, time: "2021-05-02 05:12:45.123" ,
   id: 1, time: "2021-05-01 12:12:45.123" ,
   id: 2, time: "2021-05-01 05:12:45.123" ,
   id: 2, time: "2021-05-01 04:12:45.123" ,
   id: 3, time: "2021-05-01 10:12:45.123" ,
];

const result = arr.reduce((acc, curr) => 
  if (acc.length && acc[acc.length - 1].id === curr.id) 
    if (new Date(acc[acc.length - 1].time) < new Date(curr.time)) 
      acc[acc.length - 1] =  ...acc[acc.length - 1], ...curr ;
    
   else acc.push(curr);
  return acc;
, []);

console.log(result);