Optional allowallowDiskUse lets the server know if it can use disk to store temporary results for the aggregation (requires mongodb 2.6 >).allowDiskUse让服务器知道是否可以使用磁盘存储聚合的临时结果（需要mongodb 2.6>）。
Optional authdbOptional batchThe number of documents to return per batch.每批要返回的文档数。
Optional bsonreturn BSON regular expressions as BSONRegExp instances.将BSON正则表达式作为BSONRegExp实例返回。
false
Optional bypassAllow driver to bypass schema validation.允许驱动程序绕过架构验证。
Optional checkthe serializer will check if keys are valid.序列化程序将检查键是否有效。
false
Optional collationSpecify collation.指定排序规则。
Optional commentComment to apply to the operation.要应用于操作的注释。
In server versions pre-4.4, 'comment' must be string. A server error will be thrown if any other type is provided.在4.4之前的服务器版本中，“comment”必须是字符串。如果提供了任何其他类型，则会引发服务器错误。
In server versions 4.4 and above, 'comment' can be any valid BSON type.在服务器版本4.4及更高版本中，“comment”可以是任何有效的BSON类型。
Optional cursorReturn the query as cursor, on 2.6 > it returns as a real cursor on pre 2.6 it returns as an emulated cursor.将查询作为游标返回，在2.6>上，它将作为实际游标返回。在2.6之前，它将以模拟游标的形式返回。
Optional dbOptional enableEnable utf8 validation when deserializing BSON documents. Defaults to true.在反序列化BSON文档时启用utf8验证。默认为true。
Optional explainSpecifies the verbosity mode for the explain output.指定解释输出的详细模式。
Optional fieldsallow to specify if there what fields we wish to return as unserialized raw buffer.允许指定我们希望返回哪些字段作为未序列化的原始缓冲区。
null
Optional fullAllowed values: 'updateLookup', 'whenAvailable', 'required'.允许的值：“updateLookup”、“whenAvailable”、“required”。
When set to 'updateLookup', the change notification for partial updates will include both a delta describing the changes to the document as well as a copy of the entire document that was changed from some time after the change occurred.当设置为“updateLookup”时，部分更新的更改通知将包括描述文档更改的增量，以及更改发生后某个时间更改的整个文档的副本。
When set to 'whenAvailable', configures the change stream to return the post-image of the modified document for replace and update change events if the post-image for this event is available.如果设置为“whenAvailable”，则配置更改流以返回修改文档的后图像，用于替换和更新更改事件（如果此事件的后图像可用）。
When set to 'required', the same behavior as 'whenAvailable' except that an error is raised if the post-image is not available.当设置为“required”时，与“whenAvailable”的行为相同，只是如果后期图像不可用，则会引发错误。
Optional fullAllowed values: 'whenAvailable', 'required', 'off'.允许的值：“whenAvailable”、“required”、“off”。
The default is to not send a value, which is equivalent to 'off'.默认情况是不发送值，这相当于“off”。
When set to 'whenAvailable', configures the change stream to return the pre-image of the modified document for replace, update, and delete change events if it is available.当设置为“whenAvailable”时，将更改流配置为返回修改文档的预图像，以便在更改事件可用时替换、更新和删除更改事件。
When set to 'required', the same behavior as 'whenAvailable' except that an error is raised if the pre-image is not available.当设置为“required”时，与“whenAvailable”的行为相同，只是如果预映像不可用，则会引发错误。
Optional hintAdd an index selection hint to an aggregation command向聚合命令添加索引选择提示
Optional ignoreserialize will not emit undefined fields note that the driver sets this to 序列化不会发出未定义的字段。请注意，驱动程序将其设置为falsefalse
true
Optional letMap of parameter names and values that can be accessed using $$var (requires MongoDB 5.0).可以使用$$var访问的参数名称和值的映射（需要MongoDB 5.0）。
Optional maxThe maximum amount of time for the server to wait on new documents to satisfy a change stream query.服务器等待新文档以满足更改流查询的最长时间。
Optional maxspecifies a cumulative time limit in milliseconds for processing operations on the cursor. MongoDB interrupts the operation at the earliest following interrupt point.指定处理游标上的操作的累积时间限制（以毫秒为单位）。MongoDB在以下最早的中断点中断操作。
Optional noOptional omitOptional outOptional promotewhen deserializing a Binary will return it as a node.js Buffer instance.当反序列化Binary时，它将作为nodejs Buffer实例返回。
false
Optional promotewhen deserializing a Long will fit it into a Number if it's smaller than 53 bits.当反序列化Long时，如果它小于53位，则将其放入Number中。
true
Optional promotewhen deserializing will promote BSON values to their Node.js closest equivalent types.反序列化时将BSON值提升为其Node.js最接近的等效类型。
true
Optional rawEnabling the raw option will return a Node.js Buffer which is allocated using allocUnsafe API. 启用raw选项将返回使用allocUnsafe API分配的Node.js缓冲区。See this section from the Node.js Docs here for more detail about what "unsafe" refers to in this context. 请参阅Node.js文档中的这一部分，了解有关“不安全”在本文中所指内容的更多详细信息。If you need to maintain your own editable clone of the bytes returned for an extended life time of the process, it is recommended you allocate your own buffer and clone the contents:如果您需要维护自己的可编辑字节克隆，以延长进程的使用寿命，建议您分配自己的缓冲区并克隆内容：
const raw = await collection.findOne({}, { raw: true });
const myBuffer = Buffer.alloc(raw.byteLength);
myBuffer.set(raw, 0);
// Only save and use `myBuffer` beyond this point仅在此点之后保存和使用“myBuffer”
Please note there is a known limitation where this option cannot be used at the MongoClient level (see NODE-3946).请注意，有一个已知的限制，即此选项不能在MongoClient级别使用（请参阅NODE-3946）。
It does correctly work at 它在Db, Collection, and per operation the same as other BSON options work.Db、Collection和每个操作中都能正常工作，与其他BSON选项的工作方式相同。
Optional readSpecify a read concern and level for the collection. (only MongoDB 3.2 or higher supported)指定集合的读取关注和级别。（仅支持MongoDB 3.2或更高版本）
Optional readThe preferred read preference (ReadPreference.primary, ReadPreference.primary_preferred, ReadPreference.secondary, ReadPreference.secondary_preferred, ReadPreference.nearest).首选读取首选项（ReadPreference.primary、ReadPreference.primary_preferred、ReadPreference.secondary、ReadPreference.secondary_preferred、ReadPreference.nearest）。
Optional resumeAllows you to start a changeStream after a specified event.允许您在指定事件之后启动changeStream。
Optional retryShould retry failed writes应重试失败的写入
Optional serializeserialize the javascript functions序列化javascript函数
false
Optional sessionSpecify ClientSession for this command为此命令指定ClientSession
Optional showWhen enabled, configures the change stream to include extra change events.启用时，将更改流配置为包括额外的更改事件。
Optional startSimilar to resumeAfter, but will allow you to start after an invalidated event.类似于resumeAfter，但允许您在无效事件后启动。
Optional startWill start the changeStream after the specified operationTime.将在指定的operationTime之后启动changeStream。
Optional usewhen deserializing a Long return as a BigInt.当反序列化一个Long时，指示是否可以以BigInt的形式返回。
false
Optional willGenerated using TypeDoc
Options that can be passed to a ChangeStream.可以传递给ChangeStream的选项。Note that startAfter, resumeAfter, and startAtOperationTime are all mutually exclusive, and the server will error if more than one is specified.请注意，startAfter、resumeAfter和startAtOperationTime都是互斥的，如果指定了多个，服务器将出错。