Access document in pre hook query middleware #8218

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1. BenSower commented on Oct 7, 2019

   

   BenSower

   on Oct 7, 2019

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   I am not sure if I understand correctly, but I believe accessing the document before updating it through a findOneAndUpdate hook is not possible, as this operation is an atomic one and is not being split into multiple "parts", therefor mongoose does not actually "know" what the document looks like while handling this query. Because of this, the "this" only refers to the query and not the document. However, you can of course first fetch the object through findOne or findById, and then call "save()" on it, which will give you the document in the pre('save') hook of the model.
2. vkarpov15 commented on Oct 9, 2019

   

   vkarpov15

   on Oct 9, 2019

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   @BenSower is right, you would need to execute a separate query to get the document being updated in pre('findOneAndUpdate'), because findOneAndUpdate is a single atomic operation sent to mongodb. You can access the document in post('findOneAndUpdate') though
3. vkarpov15

   closed this as completedon Oct 9, 2019
4. vkarpov15

   added

   docsThis issue is due to a mistake or omission in the mongoosejs.com documentationThis issue is due to a mistake or omission in the mongoosejs.com documentation

   on Oct 9, 2019
5. vkarpov15

   reopened this on Oct 9, 2019
6. vkarpov15

   added this to the 5.7.5 milestone on Oct 9, 2019
7. vkarpov15

   closed this as completedin b9c1012on Oct 11, 2019
8. miadabdi commented on Sep 14, 2020

   

   miadabdi

   on Sep 14, 2020

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   This is the documentation:
   You cannot access the document being updated in pre('updateOne') or pre('findOneAndUpdate') query middleware. If you need to access the document that will be updated, you need to execute an explicit query for the document.

   schema.pre('findOneAndUpdate', async function() {
     const docToUpdate = await this.model.findOne(this.getQuery());
     console.log(docToUpdate); // The document that `findOneAndUpdate()` will modify
   });
   

   However, if you define pre('updateOne') document middleware, this will be the document being updated. That's because pre('updateOne') document middleware hooks into Document#updateOne() rather than Query#updateOne().

   schema.pre('updateOne', { document: true, query: false }, function() {
     console.log('Updating');
   });
   const Model = mongoose.model('Test', schema);
   
   const doc = new Model();
   await doc.updateOne({ $set: { name: 'test' } }); // Prints "Updating"
   
   // Doesn't print "Updating", because `Query#updateOne()` doesn't fire
   // document middleware.
   await Model.updateOne({}, { $set: { name: 'test' } });
   
9. vkarpov15 commented on Sep 19, 2020

   

   vkarpov15

   on Sep 19, 2020

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   @MichaelMikeJones I opened up #9434 to fix that 👍
10. Automattic

    locked and limited conversation to collaborators on Sep 19, 2020
11. vkarpov15 commented on Sep 22, 2020

    

    vkarpov15

    on Sep 22, 2020

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    Actually @MichaelMikeJones the docs describe the behavior correctly, they mention the difference between pre('updateOne') query middleware and document middleware.