FirebaseFirestore Framework Reference

Protocols

The following protocols are available globally.

• ListenerRegistration

  Represents a listener that can be removed by calling remove.

  Declaration

  Swift

  protocol ListenerRegistration : NSObjectProtocol

• LocalCacheSettings

  Marker protocol implemented by all supported cache settings.

  The two cache types supported are PersistentCacheSettings and MemoryCacheSettings. Custom implementation is not supported.

  Declaration

  Swift

  protocol LocalCacheSettings

• MemoryGarbageCollectorSettings

  Marker protocol implemented by all supported garbage collector settings.

  The two cache types supported are MemoryEagerGCSettings and MemoryLRUGCSettings. Custom implementation is not supported.

  Declaration

  Swift

  protocol MemoryGarbageCollectorSettings

• DocumentIDWrappable

  A type that can initialize itself from a Firestore DocumentReference, which makes it suitable for use with the @DocumentID property wrapper.

  Firestore includes extensions that make String and DocumentReference conform to DocumentIDWrappable.

  Note that Firestore ignores fields annotated with @DocumentID when writing so there is no requirement to convert from the wrapped type back to a DocumentReference.

  Declaration

  Swift

  public protocol DocumentIDWrappable

• ServerTimestampWrappable

  A type that can initialize itself from a Firestore Timestamp, which makes it suitable for use with the @ServerTimestamp property wrapper.

  Firestore includes extensions that make Timestamp and Date conform to ServerTimestampWrappable.

  Declaration

  Swift

  public protocol ServerTimestampWrappable

• Expression

  Undocumented

  Declaration

  Swift

  public protocol Expression : Sendable

• BooleanExpression

  A BooleanExpression is an Expression that evaluates to a boolean value.

  It is used to construct conditional logic within Firestore pipelines, such as in where clauses or ConditionalExpression. BooleanExpression instances can be combined using standard logical operators (&&, ||, !, ^) to create complex conditions.

  Example usage in a where clause:

  firestore.pipeline()
    .collection("products")
    .where(
      Field("price").greaterThan(100) &&
      (Field("category").equal("electronics") || Field("on_sale").equal(true))
    )
  

  Declaration

  Swift

  public protocol BooleanExpression : Expression

• Selectable

  A protocol for expressions that have a name.

  Selectable is adopted by expressions that can be used in pipeline stages where a named output is required, such as select and distinct.

  A Field is a Selectable where the name is the field path.

  An expression can be made Selectable by giving it an alias using the .as() method.

  Declaration

  Swift

  public protocol Selectable : Sendable