Get documents given a range (up and down, not between) - mongodb

Question

Is it possible to get the documents that, given a date, obtain the closest to that date both above and below, I mean, greater and lower from that date.
Current code:
db.collection.aggregate({
$match: {
$or: [
{
"timestamp": {
$gte: new Date("2021-05-27T14:40:46Z")
}
},
{
"timestamp": {
$lt: new Date("2021-05-27T14:40:46Z")
}
}
]
}
},
{
$limit: 5
})
Playground

Answer 1

I don't think is there any way to do this straightway, temporary you can try the below query if it's really required,
$facet to separate the result for old date and new date as per conditions
old,
$match to check $lt condition
$sort by timestamp in descending order
$limit 2 documents
$sort by timestamp in ascending order
new,
$match to check $gte condition
$sort by timestamp in ascending order
$limit 3 documents
$project, $concatArrays to concat both arrays in single
The below process is optional if you want to format exactly what you need then use,
$unwind to deconstruct the above array
$replaceRoot to replace docs object to root
db.collection.aggregate([
{
$facet: {
old: [
{
$match: {
timestamp: {
$lt: new Date("2021-05-27T14:40:46Z")
}
}
},
{ $sort: { timestamp: -1 } },
{ $limit: 2 },
{ $sort: { timestamp: 1 } }
],
new: [
{
$match: {
timestamp: {
$gte: new Date("2021-05-27T14:40:46Z")
}
}
},
{ $sort: { timestamp: 1 } },
{ $limit: 3 }
]
}
},
{ $project: { docs: { $concatArrays: ["$old", "$new"] } } },
{ $unwind: "$docs" },
{ $replaceRoot: { newRoot: "$docs" } }
])
Playground