ByteLengthQueuingStrategy: highWaterMark property

{{APIRef("Streams")}}{{AvailableInWorkers}}

The read-only ByteLengthQueuingStrategy.highWaterMark property returns the total number of bytes that can be contained in the internal queue before backpressure is applied.

[!NOTE] Unlike CountQueuingStrategy() where the highWaterMark property specifies a simple count of the number of chunks, with ByteLengthQueuingStrategy(), the highWaterMark parameter specifies a number of bytes — specifically, given a stream of chunks, how many bytes worth of those chunks (rather than a count of how many of those chunks) can be contained in the internal queue before backpressure is applied.

Values

An integer.

Examples

const queuingStrategy = new ByteLengthQueuingStrategy({
  highWaterMark: 1 * 1024,
});

const readableStream = new ReadableStream(
  {
    start(controller) {
      // …
    },
    pull(controller) {
      // …
    },
    cancel(err) {
      console.log("stream error:", err);
    },
  },
  queuingStrategy,
);

const size = queuingStrategy.size(chunk);
console.log(`highWaterMark value: ${queuingStrategy.highWaterMark}$`);

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("ByteLengthQueuingStrategy.ByteLengthQueuingStrategy", "ByteLengthQueuingStrategy()")}} constructor