代码之家 › 专栏 › 技术社区 › Kevin.a

按日期对数组排序意外结果

sorting javascript

-1

Kevin.a · 技术社区 · 5 年前

我有一个数组包含日期,有时不包含:

const activities = [
    { title: 'Hikin'},
  { title: 'Hiking', date: '2020-12-23' },
  { title: 'Shopping', date: '2020-12-18' },
]

const activities = [
    { title: 'Hikin'},
  { title: 'Hiking', date: '2020-12-23' },
  { title: 'Shopping', date: '2020-12-18' },
]

const sortedActivities = activities.sort((a, b) => new Date(b.date)  - new Date(a.date))

console.log(sortedActivities.map(item => {
    return item.title;
}))

但问题是,没有日期的项目总是排在首位。我希望有日期的项目优先于不包含日期值的项目。

4 回复 | 直到 5 年前

Harinder Singh 5 年前

更改排序函数中的比较方法。这样地:

activities.sort((a, b) => {
  if (!a.date) return 1;
  if (!b.date) return -1;
  return new Date(b.date) - new Date(a.date);
});

Mujibur Rehman Ansari Sadegh Ghafari Yazdi 5 年前

我做的是先删除日期,然后应用过滤器,最后我只是合并排序的数据和没有日期的数据。

const activities = [
  { title: 'Hikin'},
  { title: 'Hiking', date: '2020-12-23' },
  { title: 'Shopping', date: '2020-12-18' },
];

const activitesWithoutDate = activities.filter(a => a.date === undefined);
const activitesWithDate = activities.filter(a => a.date !== undefined);

const sortedActivities = activitesWithDate.sort((a, b) => new Date(b.date)  - new Date(a.date));

console.log([...sortedActivities, ...activitesWithoutDate].map(item => item.title ));

Alan Omar 5 年前

epoch point 作为没有 date 属性:

 const activities = [
    { title: 'Hikin'},
    { title: 'Hiking', date: '2020-12-23' },
    { title: 'Shopping', date: '2020-12-18' },
 ]

 const sortedActivities = activities.sort((a, b) => new Date(b.date || '1970-01-01')  - new Date(a.date||'1970-01-01'))

 console.log(sortedActivities.map(item => {
return item.title;
}))

Adnan Ahmed 5 年前

const activities = [
    { title: 'Hikin'},
    { title: 'Hiking', date: '2020-12-23' },
    { title: 'Hikin2'},
    { title: 'Shopping', date: '2020-12-18' },
    { title: 'Hikin3'},
]

const sortedActivities = activities.sort((a, b) => {
    if(!b.date && !a.date) { return 0 }; // if both don't have date do not sort.
    if(!b.date) { return -1 }; // a comes first
    if(!a.date) { return 1 }; // b comes first
    let calValue = new Date(b.date)  - new Date(a.date); 
    return calValue;
})

console.log(sortedActivities.map(item => {
    return item.title;
}))

-1

kuka0len 5 年前

const activities = [
  { title: "Hikin" },
  { title: "Hiking", date: "2020-12-23" },
  { title: "Shopping", date: "2020-12-18" },
];

const sortedActivities = activities.sort(
  (a, b) => new Date(b.date) - new Date(a.date) || -Infinity
);

console.log(
  sortedActivities.map((item) => {
    return item.title;
  })
);