javascript - 按日期对嵌套的对象数组进行排序

Question

我正在尝试对如下所示的数组进行排序:

var dateGroups = [
  [
     {age:20, date: Fri Feb 03 2012 14:30:00 GMT+1100 (EST)}, 
     {age:12, date: Fri Feb 03 2012 18:20:00 GMT+1100 (EST)}, 
     {age:18, date: Fri Feb 03 2012 21:43:00 GMT+1100 (EST)}
  ],
  [
     {age:32, date: Fri Feb 01 2012 10:54:00 GMT+1100 (EST)}, 
     {age:44, date: Fri Feb 01 2012 11:45:00 GMT+1100 (EST)}, 
  ],
  [
     {age:22, date: Fri Feb 05 2012 10:54:00 GMT+1100 (EST)}, 
     {age:22, date: Fri Feb 05 2012 18:22:00 GMT+1100 (EST)},
  ]
]

dateGroups 的嵌套数组中的对象已经按升序排序，但我还想根据分组的日期对数组本身进行排序。

在这种情况下，数组应该如下所示:

var dateGroups = [
  [
     {age:32, date: Fri Feb 01 2012 10:54:00 GMT+1100 (EST)}, 
     {age:44, date: Fri Feb 01 2012 11:45:00 GMT+1100 (EST)}, 
  ],
  [
     {age:20, date: Fri Feb 03 2012 14:30:00 GMT+1100 (EST)}, 
     {age:12, date: Fri Feb 03 2012 18:20:00 GMT+1100 (EST)}, 
     {age:18, date: Fri Feb 03 2012 21:43:00 GMT+1100 (EST)}
  ],
  [
     {age:22, date: Fri Feb 05 2012 10:54:00 GMT+1100 (EST)}, 
     {age:22, date: Fri Feb 05 2012 18:22:00 GMT+1100 (EST)},
  ]
]

用于排序的函数还应返回 dateGroups 的新排序版本。

我试过使用 Underscore.js 的 sortBy()函数，但我无法弄清楚如何根据其中一个对象内的属性值对数组进行排序。有没有一种特定的方法来对 Date 对象进行排序？或者它们的排序方式与数字或字母相同？

Answer 1

根据 Underscore.js 文档，您应该为此简单地编写自己的迭代器。像这样:

_.sortBy(dateGroups, function(arrayElement) {
    //element will be each array, so we just return a date from first element in it
    return arrayElement[0].date.getTime();
});