MongoDb select objects from an array where object property matches coondition - arrays

Question

I'm relatively new to mongoose and nodejs. And i'm trying to hackup a quick server side script in nodejs.
I'm trying to retrieve data as array of objects from mongoDb using mongoose.
Here is what my Schema looks like -
var heatmapSchema = new Schema({
vuid: String
coordinates: [
{
x: Number,
y: Number,
c: Number,
timestamp: Number
}
]
}, {collection: collectionName} );
As you can see coordinates is an array of objects. I want to query mongoDb so I get an array of these coordinate objects, where c = 1 (c property in coordinate equals 1) i.e. -
[
{
x: 100,
y: 230,
c: 1,
timestamp: 1233312312
},
{
x: 120,
y: 240,
c: 1,
t: 1233313425
}
......
]
What would be the best way to achieve this in mongoose?
UPDATE
The closest I have gotten so far is using the below query -
heatmapModel.aggregate(
[
{
$unwind: '$coordinates'
},
{
$match: {
'coordinates.c': 1
}
},
{
$project: {
'_id': 0,
'coordinates.x': 1,
'coordinates.y': 1,
'coordinates.c': 1,
'coordinates.timestamp': 1
}
}
],
function (err, result) {
if (err) {
console.log(err);
process.exit(1);
}
console.log(result);
process.exit();
}
);
Which gives me the following output -
[ { coordinates: { x: 601, y: 165, c: 1, timestamp: 1438840800424 } },
{ coordinates: { x: 484, y: 192, c: 1, timestamp: 1438840801211 } },
{ coordinates: { x: 484, y: 192, c: 1, timestamp: 1438840801388 } },
{ coordinates: { x: 414, y: 394, c: 1, timestamp: 1438840802378 } },
.....
]
How do I get rid of the unwanted coordinates key in the json?

Answer 1

heatMap.find({'coordinates.c': 1}); should work.