How do I group the date field one to the next one in each document?
{
_id: ObjectId('...'),
date: [ISODate('2022-05-27T00:00:00.000+00:00'), ISODate('2022-05-28T00:00:00.000+00:00') ...]
}
The desired document would like this:
{
_id: ObjectId('...'),
date1: ISODate('2022-05-27T00:00:00.000+00:00'),
date2: ISODate('2022-05-28T00:00:00.000+00:00')
}
Here's one way to do it.
db.collection.aggregate([
{ "$replaceWith": {
"$mergeObjects": [
{ "_id": "$_id" },
{ "$arrayToObject": {
"$map": {
"input": { "$range": [ 0, { "$size": "$date" } ] },
"as": "dateNum",
"in": {
"k": {
"$concat": [
"date",
{ "$toString": { "$add": [ "$$dateNum", 1 ] } }
]
},
"v": { "$arrayElemAt": [ "$date", "$$dateNum" ] }
}
}
}
}
]
}
}
])
Try it on mongoplayground.net.