mongoose aggregate unwind code example

Example 1: mongodb unwind

{
  $unwind:
    {
      path: <field path>,
      includeArrayIndex: <string>,
      // to include documents whose sizes field is null, missing, or an empty array.
      preserveNullAndEmptyArrays: <boolean>
    }
}

Example 2: how to use mongoose aggregate

new Aggregate([{ $match: { _id: '00000000000000000000000a' } }]);
  // Do this instead to cast to an ObjectId
  new Aggregate([{ $match: { _id: mongoose.Types.ObjectId('00000000000000000000000a') } }]);