Moongoose aggregate $match does not match id’s

by

Your ids variable will be constructed of “strings”, and not ObjectId values.

Mongoose “autocasts” string values for ObjectId into their correct type in regular queries, but this does not happen in the aggregation pipeline, as in described in issue #1399.

Instead you must do the correct casting to type manually:

ids = ids.map(function(el) { return mongoose.Types.ObjectId(el) })

Then you can use them in your pipeline stage:

{ "$match": { "_id": { "$in": ids } } }

The reason is because aggregation pipelines “typically” alter the document structure, and therefore mongoose makes no presumption that the “schema” applies to the document in any given pipeline stage.

It is arguable that the “first” pipeline stage when it is a $match stage should do this, since indeed the document is not altered. But right now this is not how it happens.

Any values that may possibly be “strings” or at least not the correct BSON type need to be manually cast in order to match.

More Related Contents:

  1. Does MongoDB’s $in clause guarantee order
  2. How to return just the nested documents of an array from all documents
  3. MongoDB: Calculate dwell time between every status value change
  4. MongoDB: how to parse date in 3.6 mongoDb version?
  5. Mongodb aggregation $group, restrict length of array
  6. $project in $lookup mongodb
  7. Mongodb, aggregate query with $lookup
  8. Get names of all keys in the collection
  9. How to filter array in subdocument with MongoDB [duplicate]
  10. MongoDB: Combine data from multiple collections into one..how?
  11. $lookup multiple levels without $unwind?
  12. Find in Double Nested Array MongoDB
  13. Conditional $sum in MongoDB
  14. arrayFilters in mongodb
  15. Get a count of total documents with MongoDB when using limit
  16. Include all existing fields and add new fields to document
  17. exclude fields in $lookup aggregation
  18. MongoDB aggregation comparison: group(), $group and MapReduce
  19. Add some kind of row number to a mongodb aggregate command / pipeline
  20. MongoDB group by array inner-elements
  21. Exception: can’t convert from BSON type EOO to Date
  22. Multiple Counts with single query in mongodb
  23. MongoDB sort documents by array elements
  24. How to return array of string with mongodb aggregation
  25. MongoDB – get documents with max attribute per group in a collection
  26. Geospatial $near within current document field value
  27. Mongodb aggregation pipeline how to limit a group push
  28. Find documents whose array field contains at least n elements of a given array
  29. mongodb aggregate query isn’t returning proper sum on using $sum
  30. MongoDB aggregate within daily grouping [duplicate]

Leave a Comment