Use Getters and Setters to Modify Data
To execute logic each time a public property is set, write a custom setter.
If you write a setter for a public property, you must also write a getter. Annotate either the getter or the setter with @api, but not both. It’s a best practice to annotate the getter.
To hold the property value inside the getter and setter, use a field. This example uses the _uppercaseItemName property, which is prefixed with an underscore to indicate that the property is private.
This sample <c-todo-item> component converts a string to uppercase.
The property value is provided to the template via the getter.
For another example of using a getter and setter, see the apiSetterGetter and todoList components in the lwc-recipes sample repo.
See Also