Mongoose JobSchema.pre ('update' , function(n){n()}) 抛出 : TypeError: Cannot read property 'numAsyncPres' of undefined

Question

我在 mongoose 中有这个架构，当我使用 pre 和 update 时，出现此错误。

JobSchema.pre('update', function(n){n()})

完全错误

C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\utils.js:413
        throw err;
              ^
TypeError: Cannot read property 'numAsyncPres' of undefined
    at Model._lazySetupHooks (C:\web\production01_server\node_modules\production\node_modules\mongoose\node_modules\hooks\hooks.js:149:49)
    at Model.pre (C:\web\production01_server\node_modules\production\node_modules\mongoose\node_modules\hooks\hooks.js:113:10)
    at Model.doQueue (C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\document.js:1116:41)
    at Model.Document (C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\document.js:55:8)
    at Model.Model (C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\model.js:26:12)
    at Model.model (C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\model.js:910:11)
    at new Model (C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\connection.js:418:15)
    at cb (C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\query.js:804:16)
    at C:\web\production01_server\node_modules\production\node_modules\mongoose\lib\utils.js:408:16
    at C:\web\production01_server\node_modules\production\node_modules\mongoose\node_modules\mongodb\lib\mongodb\cursor.js:133:9

笔记:

预('保存'作品

post('update' 不会抛出错误并且不起作用

Answer 1

Mongoose 4.0 通过查询中间件支持预更新 Hook 。
http://mongoosejs.com/docs/middleware.html

schema.pre('update', function() {
  console.log(this instanceof mongoose.Query); // true
  this.start = Date.now();
});

schema.post('update', function() {
  console.log(this instanceof mongoose.Query); // true
  console.log('update() took ' + (Date.now() - this.start) + ' millis');
});

注意事项:

"Query middleware differs from document middleware in a subtle but important way: in document middleware, this refers to the document being updated. In query middleware, mongoose doesn't necessarily have a reference to the document being updated, so this refers to the query object rather than the document being updated."