@BeforeInsert

function BeforeInsert(): PropertyDecorator;

A PropertyDecorator factory applied to a method — registers that method under the 'before-insert' bucket on the entity's EntityMetadata.eventListeners:

class Customer {
  @BeforeInsert()
  validate(): void {
    // ...
  }
}

Throws You can define a Column for only string properties if applied to a symbol-keyed property, and Property must be a function if the decorated property isn't a function.

Not currently invoked automatically

As of this version of @sqb/connect, nothing in Repository or the create/update/delete command implementations reads eventListeners back or calls the registered functions — attaching @BeforeInsert() to a method registers it as metadata only; it does not, by itself, make that method run when you call repo.create(...). See Lifecycle Hooks for the full explanation and workarounds.

See Lifecycle Hooks for the full guide and the sibling decorators: @AfterInsert, @BeforeUpdate, @AfterUpdate, @BeforeDestroy, @AfterDestroy.