MongoDB – The argument to $size must be an Array, but was of type: EOO / missing
You can use the $ifNull operator here. It seems the field is either not an array or not present by the given error: { “$project”: { “people”: 1, “Count”: { “$size”: { “$ifNull”: [ “$myFieldArray”, [] ] } } }} Also you might want to check for the $type in your $match in case these … Read more