Aggregate()

Parameters

• [pipeline] «Array» aggregation pipeline as an array of objects

Aggregate constructor used for building aggregation pipelines. Do not instantiate this class directly, use Model.aggregate() instead.

Example:

const aggregate = Model.aggregate([
  { $project: { a: 1, b: 1 } },
  { $skip: 5 }
]);
Model.
  aggregate([{ $match: { age: { $gte: 21 }}}]).
  unwind('tags').
  exec(callback);

Note:

• The documents returned are plain javascript objects, not mongoose documents (since any shape of document can be returned).
• Mongoose does not cast pipeline stages. The below will not work unless _id is a string in the database

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