如何使用两个属性对对象数组进行排序，但有条件地根据条件按排序顺序分组？

Question

这个问题是一个延续了这个问题。

假设我有一个如下所示的数组：

const questions = [
  {_id: 1, q: 'why?', group: 'no-group', date: '8', selected: false }, 
  {_id: 2, q: 'what?', group: 'group 1', date: '6', selected: false }, 
  {_id: 3, q: 'when?', group: 'no-group', date: '7', selected: false }, 
  {_id: 4, q: 'where?', group: 'group 1', date: '5', selected: false }, 
  {_id: 5, q: 'which?', group: 'group 2', date: '3', selected: false },
  {_id: 6, q: 'who?', group: 'no-group', date: '0', selected: false },
  {_id: 7, q: 'why not?', group: 'group 2', date: '9', selected: false }, 
  {_id: 8, q: 'who, me?', group: 'group 1', date: '4', selected: false }, 
  {_id: 9, q: 'where is waldo?', group: 'group 1', date: '1', selected: false }, 
  {_id: 10, q: 'which way is up?', group: 'no-group', date: '2', selected: false },
  {_id: 11, q: 'when is lunch?', group: 'group-2', date: '10', selected: false }, 
];

如何编写代码对其进行排序，以便按日期和组对对象进行排序。但是如果：假设第 1 组作为第二个对象出现，那么以下对象应该按日期排序为第 1 组，直到列出所有第 1 组对象，并且对于除具有'no-group'组属性值的对象之外的所有其他对象都相同。

所以对于上面的数组，我应该得到如下输出：

[
  {_id: 6, q: 'who?', group: 'no-group', date: '0', selected: false },

  {_id: 9, q: 'where is waldo?', group: 'group 1', date: '1', selected: false }, 
  {_id: 8, q: 'who, me?', group: 'group 1', date: '4', selected: false }, 
  {_id: 4, q: 'where?', group: 'group 1', date: '5', selected: false }, 
  {_id: 2, q: 'what?', group: 'group 1', date: '6', selected: false },

  {_id: 10, q: 'which way is up?', group: 'no-group', date: '2', selected: false },

  {_id: 5, q: 'which?', group: 'group 2', date: '3', selected: false },
  {_id: 7, q: 'why not?', group: 'group 2', date: '9', selected: false }, 
  {_id: 11, q: 'when is lunch?', group: 'group 2', date: '10', selected: false },

  {_id: 3, q: 'when?', group: 'no-group', date: '7', selected: false }, 
  {_id: 1, q: 'why?', group: 'no-group', date: '8', selected: false }, 
];

// the spacing is just for easier readability.

Answer 1

您可以通过date对相同组取消对象的排序、分组并获得平面数组。

const 
    questions = [{ _id: 1, q: 'why?', group: 'no-group', date: '8', selected: false }, { _id: 2, q: 'what?', group: 'group 1', date: '6', selected: false }, { _id: 3, q: 'when?', group: 'no-group', date: '7', selected: false }, { _id: 4, q: 'where?', group: 'group 1', date: '5', selected: false }, { _id: 5, q: 'which?', group: 'group 2', date: '3', selected: false }, { _id: 6, q: 'who?', group: 'no-group', date: '0', selected: false }, { _id: 7, q: 'why not?', group: 'group 2', date: '9', selected: false }, { _id: 8, q: 'who, me?', group: 'group 1', date: '4', selected: false }, { _id: 9, q: 'where is waldo?', group: 'group 1', date: '1', selected: false }, { _id: 10, q: 'which way is up?', group: 'no-group', date: '2', selected: false }, { _id: 11, q: 'when is lunch?', group: 'group 2', date: '10', selected: false }],
    result = questions
        .sort((a, b) => a.date - b.date)
        .map((groups => o => {
            if (o.group === 'no-group') return o;
            if (groups[o.group]) {
                groups[o.group].push(o);
                return [];
            }
            return groups[o.group] = [o];
        })({}))
        .flat();

console.log(result);

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