node.js - Mongoose:计算删除的文档

Question

如何检查 Mongoose 模型的 remove-method 是否确实删除了某些内容？

MyModel.remove({_id: myId}, function(err, entry) {
  if(entry == null) next(new Error("ID was not found."));    // this doesn't work
}

我可以查看删除了多少文档吗？

在 Mongo-Documentation Kristina1 在评论中写道:

If you call db.runCommand({getLastError:1}) after a remove and the "n" field will tell you how many documents were deleted.

但我不知道如何用 Mongoose 做到这一点。

Answer 1

Mongoose < 4，MongoDB < 3

remove 回调的第二个参数是一个数字，包含删除的文档数。

MyModel.remove({_id: myId}, function(err, numberRemoved) {
  if(numberRemoved === 0) next(new Error("ID was not found."));
}

Mongoose 4.x、MongoDB 3.x

传递给 remove 回调的第二个参数现在是一个对象，其中 result.n 字段指示已删除文档的计数:

MyModel.remove({_id: myId}, function(err, obj) {
  if(obj.result.n === 0) next(new Error("ID was not found."));
}