[{"projectName":"first","resources":[{"resource":"EC2","region":"ap-south-1","params":{"ImageId":"ami-0bcf5425cdc1d8a85","InstanceType":"t2.micro"}},{"resource":"S3","region":"ap-south-1","params":{"Bucket":"test-bucket"}}]}]

db.collection.aggregate([{$match:{resources:{$elemMatch:{resource:{$eq:"EC2"}}}}},{$replaceRoot:{newRoot:{$arrayElemAt:[{$filter:{input:"$resources",cond:{$eq:["$$this.resource","EC2"]}}},0]}}}])