How do I use middleware in Mongoose?

How do I use middleware in Mongoose?

In Mongoose, middleware are functions that are executed at specific stages of the document lifecycle. You can define middleware for operations like saving, validating, and removing documents.

Can you give me an example of a pre-save middleware?

Sure! Here's a simple example:

schema.pre('save', function(next) {
  this.updatedAt = Date.now();
  next();
});

This middleware updates the updatedAt field before saving a document.

What about post-remove middleware?

Post-remove middleware can be used to perform actions after a document is removed. For example:

schema.post('remove', function(doc) {
  console.log(`Document with id ${doc._id} was removed.`);
});

Are there any built-in middleware functions?

Yes, Mongoose provides built-in middleware like validate, save, remove, and init. You can use these to hook into the document lifecycle.