WritableStreamDefaultController.constructor

The WritableStreamDefaultController() constructor creates and returns a WritableStreamDefaultController() object instance.

Syntax

var writableStreamController = new WritableStreamDefaultController(stream, underlyingSink, size, highWaterMark);

Parameters

stream

The WritableStream to be controlled.

underlyingSink

An object containing methods and properties that define how the constructed stream instance will behave. See the WritableStream() constructor's parameter definitions for more information.

size

A method containing a parameter chunk — this indicates the size to use for each chunk, in bytes.

highWaterMark

A non-negative integer — this defines the total number of chunks that can be contained in the internal queue before backpressure is applied.

Return value

An instance of the WritableStreamDefaultController object.

Exceptions

TypeError

The supplied stream parameter is not a WritableStream, or it already has an associated controller.

Examples

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

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

Specifications

Browser compatibilityUpdate compatibility data on GitHub