Validation

Within a LoopBack application, validation can be added in various places depending on the usage. Some types of validations come out-of-the-box in LoopBack, such as type validation in the REST layer, whereas some require additional configuration or code.

There are various types of validations such as:

• validation of input/output for method invocations
• validation of model instance properties, for example, age < 0
• validation of model collections, for example, uniqueness

Let’s take a closer look at how validation can be added in the following layers:

• REST layer
• Controller, Repository and Service Layer
• ORM layer

The validation-app example application is used in the following documentation pages for demonstration. In the example, a CoffeeShop model is being used. It has the following properties.