View elements also support a few attributes that allow views to dynamically change their appearance or behavior, depending on field values. We may have on-change events, which are able to change values on other fields while editing data on a form, or have fields that are mandatory or visible only when certain conditions are met.
The on-change mechanism allows us to change values in other form fields when a particular field is changed. For example, the on-change on a product field can set the price field to a default value whenever the product is changed.
In older versions, the on-change events were defined at the view level, but since version 8.0 they are defined directly on the model layer, without the need for any specific markup on the views. This is done with creating methods, using the @api.onchange('field1', 'field2', ...) decorator to bind on-change logic to some fields. The on-change model methods are discussed in more detail in Chapter 8, Business...