Add Operation Hooks to a LoopBack model

Bram Borggreve
InstructorBram Borggreve

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In this lesson we will learn how to add operation hooks to our models. In the Product model we will create a before safe observer that will check if the category we want to add the product to exists.

In our Category model we will create a before delete observer to prevent categories from being deleted when they have products.

We will create a unit test to verify that both of these operation hooks work as expected.

Victor Hazbun
Victor Hazbun
~ 4 years ago

why the product hook returns next() and the category model does not?

Frederic Rey
Frederic Rey
~ 3 years ago

Hello! It seems we can do the same with an Async Validator, is there an advantage using a Hook over it ? What I can see is:

  • With a Validator, only the current Model Instance is available, unless the Model itself is in a parent scope (which is the case) or injected
  • With a Hook, at least the current Model instance and every Model are available