# CustomMapping

    public enum CustomMapping : Hashable

Provides the type of mapping for an entity. Mappings of entities with no `CustomMapping` provided will be automatically calculated if possible. Any conflicts or ambiguity will raise an assertion.

- `deleteEntity(sourceEntity:)`

  The `sourceEntity` is meant to be removed from the source `DynamicSchema` and should not be migrated to the destination `DynamicSchema`.

  #### Declaration

  Swift

      case deleteEntity(sourceEntity: EntityName)

- `insertEntity(destinationEntity:)`

  The `destinationEntity` is newly added to the destination `DynamicSchema` and has no mapping from the source `DynamicSchema`.

  #### Declaration

  Swift

      case insertEntity(destinationEntity: EntityName)

- `copyEntity(sourceEntity:destinationEntity:)`

  The `DynamicSchema`s entity has no changes and can be copied directly from `sourceEntity` to `destinationEntity`.

  #### Declaration

  Swift

      case copyEntity(sourceEntity: EntityName, destinationEntity: EntityName)

- `transformEntity(sourceEntity:destinationEntity:transformer:)`

  The `DynamicSchema`s entity needs transformations from `sourceEntity` to `destinationEntity`. The `transformer` closure will be used to apply the changes. The `CustomMapping.inferredTransformation` method can be used directly as the `transformer` if the changes can be inferred (i.e. lightweight).

  #### Declaration

  Swift

      case transformEntity(sourceEntity: EntityName, destinationEntity: EntityName, transformer: Transformer)

- `Transformer`

  The closure type for `CustomMapping.transformEntity`.

  #### Declaration

  Swift

      public typealias Transformer = (_ sourceObject: UnsafeSourceObject, _ createDestinationObject: () -> UnsafeDestinationObject) throws -> Void

  #### Parameters

  `sourceObject` | a proxy object representing the source entity. The properties can be accessed via keyPath.

  `createDestinationObject`

  the closure to create the object for the destination entity. The `CustomMapping.inferredTransformation` method can be used directly as the `transformer` if the changes can be inferred (i.e. lightweight). The object is created lazily and executing the closure multiple times will return the same instance. The destination object’s properties can be accessed and updated via keyPath.

- `inferredTransformation(_:_:)`

  The `CustomMapping.inferredTransformation` method can be used directly as the `transformer` if the changes can be inferred (i.e. lightweight).

  #### Declaration

  Swift

      public static func inferredTransformation(_ sourceObject: UnsafeSourceObject, _ createDestinationObject: () -> UnsafeDestinationObject) throws

### Equatable

- `==(_:_:)`

  #### Declaration

  Swift

      public static func == (lhs: CustomMapping, rhs: CustomMapping) -> Bool

### Hashable

- `hash(into:)`

  #### Declaration

  Swift

      public func hash(into hasher: inout Hasher)