Using Mongoose middleware
Mongoose middleware are functions that can intercept the process of the init
, validate
, save
, and remove
instance methods. Middleware are executed at the instance level and have two types: pre middleware and post middleware.
Using pre middleware
Pre middleware gets executed before the operation happens. For instance, a pre-save middleware will get executed before the saving of the document. This functionality makes pre middleware perfect for more complex validations and default values assignments.
A pre middleware is defined using the pre()
method of the schema object, so validating your model using a pre middleware will look like what is shown in the following code snippet:
UserSchema.pre('save', function(next){ if (...) ...
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