如何在元数据库MongoDB原生查询中引用“当前日期”？

db.collection.find({
  $expr: {
    $eq: [
      { $dateToString: { format: "%Y-%m-%d", date: new Date() } },
      { $dateToString: { format: "%Y-%m-%d", date: "$dateField" } }
    ]
  }
})

db.collection.find({
  $expr: {
    $gte: [
      { $dateToString: { format: "%Y-%m-%d", date: new Date() } },
      { $dateToString: { format: "%Y-%m-%d", date: "$dateField" } }
    ]
  }
})