node.js - Mongoose :中间件预删除选项不起作用

Question

Mongoose 的文档说:

Mongoose - Schema-pre

Schema.prototype.pre():
Parameters:
The «String|RegExp» method name or regular expression to match method name
[options] «Object»
[options.document] «Boolean» If name is a hook for both document and query middleware, set to true to run on document middleware.
[options.query] «Boolean» If name is a hook for both document and query middleware, set to true to run on query middleware.
callback «Function»

还有关于 pre hook“deleteOne”:
Mongoose - middleware

Document middleware is supported for the following document functions. In document middleware functions, this refers to the document:
...deleteOne

Query middleware is supported for the following Model and Query functions. In query middleware >functions, this refers to the query:
...deleteOne

所以，deleteOne 位于 Document 和 Query Hook 中，现在让我们尝试使用它:

mySchema.pre('deleteOne', { document: true }, function(next) {
  console.log(this)
  next()
})

结果:这是指查询，而不是文档。为什么？

Answer 1

哦，文档中并不清楚，“this”仅指文档#deleteOne中的文档。

因此，“deleteOne”钩子(Hook)的正确用法是:
在模型中:

DocSchema.pre('deleteOne', { document: true }, function(next) {
  console.log(this)
  next()
})

稍后在代码中(在 Controller 等中):

const doc = await DocModel.findOne({ name: 'myDoc' })
await doc.deleteOne()

现在“this”指的是文档🎉