JavaScript:返回关联数组而不是普通数组

Question

我指的是this answer再次。

var firstEvents = events.reduce(function(ar, e) {
  var id = e.getId();
  if (e.isRecurringEvent() && e.isAllDayEvent() && !ar.some(function(f) {return f.eventId == id})) {
    ar.push({eventTitle: e.getTitle(), eventId: id, startDate: e.getAllDayStartDate(), endDate: e.getAllDayEndDate()});
  }
  return ar;
}, []);

我需要更改什么才能获取一个以事件标题(字符串)为键、以开始日期(日期对象)为值的数组，以便我可以通过 firstEvents['some event title'] 检索某个开始日期(日期对象) ？

编辑:

当前输出:

firstEvents = [{eventTitle=Event title 1, eventId=xyz1@google.com, startDate=Sun Mar 18 00:00:00 GMT+01:00 2018, endDate=Mon Mar 19 00:00:00 GMT+01:00 2018},
               {eventTitle=Event title 2, eventId=xyz2@google.com, startDate=Tue Mar 19 00:00:00 GMT+01:00 2019, endDate=Wed Mar 20 00:00:00 GMT+01:00 2019},
               {eventTitle=Event title 3, eventId=xyz3@google.com, startDate=Fri Mar 20 00:00:00 GMT+01:00 2020, endDate=Sat Mar 21 00:00:00 GMT+01:00 2020}]

所需输出(伪):

firstEvents = ['Event title 1' => Sun Mar 18 00:00:00 GMT+01:00 2018,
               'Event title 2' => Tue Mar 19 00:00:00 GMT+01:00 2019,
               'Event title 3' => Fri Mar 20 00:00:00 GMT+01:00 2020]

Answer 1

不要使用push，而是用key设置为object。

ar = {}; // You may need to change source parameter too
// you cannot change input Array [] to Object {} type inside function
// you can get Array and return Object, but source variable will not change
ar[e.getTitle()] = e.getAllDayStartDate();

或者使用一些演示数据:

var ar = [
{
    eventTitle: 'one',
    eventId: '#1',
    startDate: new Date(),
    endDate: new Date()
},
{
    eventTitle: 'two',
    eventId: 'secondId',
    startDate: new Date(),
    endDate: new Date()
}];
var retVal = {};
for (var i of ar) {
    retVal[i.eventId] = i;
}
console.log(JSON.stringify(retVal, null, 2));
console.log(retVal['#1']);
console.log(retVal.secondId);