The WritableStreamDefaultController interface of the Streams API represents a controller allowing control of a WritableStream's state.
WritableStreamDefaultController
MDN Reference
Readonly
The read-only signal property of the WritableStreamDefaultController interface returns the AbortSignal associated with the controller.
signal
The error() method of the with the associated stream to error.
error()
Optional
The
WritableStreamDefaultControllerinterface of the Streams API represents a controller allowing control of a WritableStream's state.MDN Reference