新属性中的对象组数组

Question

[{date:'2017-8-1'},{date:'2017-8-2'},{date:'2017-8-3'},{date:'2017-8-5'},{date:'2017-8-6'},{date:'2017-8-7'},{date:'2017-8-8'},{date:'2017-8-9'}]

我有上述数据，我尝试将最后 2 项分组并给它一个属性“周末”，其余的是“工作日”，我的预期输出是这样的

{
    weekdays: [{date:'2017-8-1'},{date:'2017-8-2'},{date:'2017-8-3'},{date:'2017-8-5'},{date:'2017-8-6'},{date:'2017-8-7'}],
    weekends: [{date:'2017-8-8'},{date:'2017-8-9'}]
}

我的尝试失败了

data.map((obj, i) => {

    if(data.length - (i + 1) >= 2) {
        return {
            weekdays: {
                date: moment(obj.date)
            }
        }
    }

    return {
        weekends: {
            date: moment(obj.date)
        }
    }
})

Answer 1

如果您不确定日期的顺序：

days = [{date:'2017-8-1'},{date:'2017-8-2'},{date:'2017-8-3'},{date:'2017-8-5'},{date:'2017-8-6'},{date:'2017-8-7'},{date:'2017-8-8'},{date:'2017-8-9'}]

const isWeekend = day => (
  [6, 0].includes(new Date(day.date).getDay())
);

const separate = (days) => {
  const weekends = [];
  const weekdays = [];
  days.forEach((day) => {
    isWeekend(day) ? weekends.push(day) : weekdays.push(day);
  });
  return { weekends, weekdays };
};

console.log(separate(days));

Answer 2

如果您确定周末总是输入数组中的最后两个元素，您可以使用简单的slice。

var inputArray = [{date:'2017-8-1'},{date:'2017-8-2'},{date:'2017-8-3'},{date:'2017-8-5'},{date:'2017-8-6'},{date:'2017-8-7'},{date:'2017-8-8'},{date:'2017-8-9'}],
outputArray = {
  weekdays: inputArray.slice(0,5),
  weekends: inputArray.slice(6)
};

console.log(outputArray);

Answer 3

添加其他答案并解释您的尝试失败的原因：这是Array.reduce而不是Array.map的情况。后者旨在为输入数组中的每个元素返回一个元素，而reduce 可用于将数组“折叠”为单个值、对象或其他东西（这是我们想要的）。

一个优雅的解决方案可能如下所示：

const outObj = inArr.reduce(function(obj, current, i) {
    if(i >= 5) { // or other check for weekend, depending on your data
      return Object.assign(obj, { weekends : obj.weekends.push(current) })
    } else {
      return Object.assign(obj, { weekdays : obj.weekdays.push(current) })
    }
  }, { weekdays : [], weekends : [] })

在上面的代码 sn-p 中，我们传入的函数在每个输入元素上运行，就像 map 一样。关键的区别在于它可以访问函数最后一次运行产生的输出，该输出作为第一个参数传入（在本例中称为obj）。顺便说一下，传递给reduce 的第二个参数是obj 的初始状态（具有两个空列表的对象）。

这种方法可以逐渐填充单个对象，而不是像您的 map 版本那样创建 n 个不同的对象。

Answer 4

既然您已经在使用momenjs，那么您可以使用map() 将您的数组转换为moment 对象数组，然后使用isoWeekday() method 简单地将filter：

var array = [{date:'2017-8-1'},{date:'2017-8-2'},{date:'2017-8-3'},{date:'2017-8-5'},{date:'2017-8-6'},{date:'2017-8-7'},{date:'2017-8-8'},{date:'2017-8-9'}];

var momentArray = array.map(function(d){ return moment(d.date, "YYYY-M-D"); });

var obj = {
    weekdays: momentArray.filter(function(d){ return d.isoWeekday() < 6 }),
    weekends: momentArray.filter(function(d){ return d.isoWeekday() > 5 })
};

console.log(obj);

<script src="//cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js"></script>

Answer 5

您可以将字符串转换为日期，然后使用.getDay() 方法来检查日期。然后将其放入相应的数组中，如下所示：

var array = [{date:'2017-8-1'},{date:'2017-8-2'},{date:'2017-8-3'},{date:'2017-8-5'},{date:'2017-8-6'},{date:'2017-8-7'},{date:'2017-8-8'},{date:'2017-8-9'}];
var obj = {
    weekdays: [],
    weekends: []
};

array.forEach((el, key) => {
    if(new Date(el.date).getDay() === 0 || new Date(el.date).getDay() === 6) obj.weekends.push(el); else obj.weekdays.push(el);
});

console.log(obj);

Answer 6

您既没有返回变量也没有返回数组。 尝试使用 foreach 并将您的属性添加到变量中。

代替您当前的解决方案，试试这个；

newOb = {};
Array.forEach((o,i)=>{
If(i>(array.length-2)-1){
newOb.weekend == undefined? newOb.weekend=[o]:newOb.weekend.push(o);}
else{
newOb.weekday == undefined? newOb.weekday = [o]: newOb.weekday.push(o);}});