CODEWITHSUNDEEP
mongodbmongoosemongodb-queryaggregation-framework
styopdev
styopdev

Reputation: 2664

How to reset mongodb aggregation limit

From mongodb cursor limit's docs

A limit() value of 0 (i.e. .limit(0)) is equivalent to setting no limit.

but I cant find way to reset query limit in mongodb aggregation limit docs.

 const listQuery = query.limit(20).exec(); //  I need limit here
 query.limit(0); // error here
 const totalQuery = query.group(....).exec(); // No limit must be specified

I am getting error

MongoError: the limit must be positive

Thanks for replies!

Upvotes: 1

Views: 3517

Answers (1)

styopdev
styopdev

Reputation: 2664

I wrote function which resets any pipeline command from aggregation

Aggregate.prototype.reset = function (command, onlyLatest) {
  command = command.replace(/^/, '$');
  let i   = this._pipeline.length;
  while (i--) {
    if (command === Object.keys(this._pipeline[i])[0]) {
      this._pipeline.splice(i, 1);
      if (onlyLatest) {
        break;
      }
    }
  }
  return this;
};

Example, useful when you have pagination

  var query = this.aggregate();
  query.match({ ... });
  query.lookup({ ... });
  query.unwind({ ... });
  query.project({ ... });
  query.sort(...);
  query.skip();
  query.limit(10);

  const listQuery  = query.exec();
  const totalQuery = query.reset('limit').reset('skip').exec();

  return Promise.all([listQuery, totalQuery]);

Upvotes: 1

Related Questions