在mongodb中匹配数组中的字段时，如何忽略其他字段？

{
  "_id": 1,
  "name": "John",
  "skills": [
    {
      "name": "Frontend",
      "level": "Intermediate"
    },
    {
      "name": "Backend",
      "level": "Advanced"
    }
  ]
},
{
  "_id": 2,
  "name": "Jane",
  "skills": [
    {
      "name": "Frontend",
      "level": "Advanced"
    },
    {
      "name": "Database",
      "level": "Intermediate"
    }
  ]
}

db.users.find(
  { skills: { $elemMatch: { name: "Frontend", level: "Advanced" } } },
  { "skills.$": 1 }
)

{
  "_id": 1,
  "skills": [
    {
      "name": "Frontend",
      "level": "Advanced"
    }
  ]
},
{
  "_id": 2,
  "skills": [
    {
      "name": "Frontend",
      "level": "Advanced"
    }
  ]
}