Mongoose aggregation: Documents with a specific object property in array of objects - mongodb

Question

Let's say you have a collections with thousands of football players like these two
[
{
"_id" : ObjectId("5e19d76fa45abb5d4d50c1d3"),
"name" : "Leonel Messi",
"country" : "Argentina",
"awards" : [
{
"award" : "Ballon d'Or",
"year" : 1972
},
{
"award" : "Golden Boot",
"year" : 1971
},
{
"award" : "FIFA World Player of the Year",
"year" : 1988
}
]
},
{
"_id" : ObjectId("53w9d76fa45abb5d4d30c112"),
"name" : "Lars Sørensen",
"country" : "Denmark",
"awards" : [
{
"award" : "Ballon d'Or",
"year" : 1971
},
]
}
]
"awards" can contain any number of objects.
I would like to return all the players, with a boolean property on whether they have won the "Golden Boot" award or not. So something like this:
[
{
"name" : "Leonel Messi",
"won_golden_boot" : true,
},
{
"name" : "Lars Sørensen",
"won_golden_boot" : false,
}
]
But I struggle to figure out how I use the aggregation stages to do this? Do I use $map? $in? and if so, how would they come ind her:
{ $sort: { name: 1 } },
// What goes here??
{
$project: {
name: "$name",
won_golden_boot: "$won?",
}
},

Answer 1

You can use this aggregation query:
This query use $project as you have done but for won_golden_boot do a condition $cond checking if exists an award called Golden Boot using $in operator.
db.collection.aggregate([
{
"$project": {
"name": "$name",
"won_golden_boot": {
"$cond": {
"if": {
"$in": [
"Golden Boot",
"$awards.award"
]
},
"then": true,
"else": false
}
}
}
}
])
Example here
Edit:
I know this is question is specifically to use aggregation, but in case is useful for somebody is possible to do this using find like this example