WritableStreamDefaultController

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since May 2022.

Note: This feature is available in Web Workers.

The WritableStreamDefaultController interface of the Streams API represents a controller allowing control of a WritableStream's state. When constructing a WritableStream, the underlying sink is given a corresponding WritableStreamDefaultController instance to manipulate.

Constructor

None. WritableStreamDefaultController instances are created automatically during WritableStream construction.

Instance properties

WritableStreamDefaultController.signal Read only

Returns the AbortSignal associated with the controller.

Instance methods

WritableStreamDefaultController.error()

Causes any future interactions with the associated stream to error.

Examples

js
const writableStream = new WritableStream({
  start(controller) {
    // do stuff with controller

    // error stream if necessary
    controller.error("My stream is broken");
  },
  write(chunk, controller) {
    // …
  },
  close(controller) {
    // …
  },
  abort(err) {
    // …
  },
});