KtMongo 0.12.0 is out, which adds support for arra...

# kmongo

[CLOVIS]

KtMongo 0.12.0 is out, which adds support for array aggregation updates.

Which do you prefer, Kotlin?

users().aggregate()
	.project {
		include(User::name)
		User::bestPassingGrades set User::grades
			.filter { it gt of(50) }
			.map { it / Grade::value }
			.sortedDescending()
			.take(of(3))
	}
	.sort { ascending(User::name) }
	.limit(2)

Or BSON?

[
	{
		"$project": {
			"name": 1,
			"bestPassingGrades": {
				"$firstN": {
					"input": {
						"$sortArray": {
							"input": {
								"$map": {
									"input": {
										"$filter": {
											"input": "$grades",
											"as": "this",
											"cond": {"$gt": ["$$this", {"$literal": 50}]}
										}
									},
									"as": "this",
									"in": {"$getField": {"input": "$$this", "field": "value"}}
								}
							},
							"sortBy": -1
						}
					},
					"n": {"$literal": 3}
				}
			}
		}
	},
	{"$sort": {"name": 1}},
	{"$limit": 2}
]

If you're in Bordeaux, France, I'm giving a talk on the KtMongo project, its current limitations, and how it can be adopted in a KMongo project, in two weeks. You can sign up for free here.

If you use aggregation pipelines, I am searching for users who use temporary variables within their pipelines to discuss how KtMongo could help. Please get in touch.

https://opensavvy.gitlab.io/ktmongo/docs/news/2025/03/01/v0.12.0.html