The WritableStream interface of the Streams API provides a standard abstraction for writing streaming data to a destination, known as a sink.
This object comes with built-in backpressure and queuing.
Aborts the stream, signaling that the producer can no longer successfully write to the stream and it is to be immediately moved to an error state, with any queued writes discarded.
Returns a new instance of WritableStreamDefaultWriter and locks the stream to that instance. While the stream is locked, no other writer can be acquired until this one is released.
The following example illustrates several features of this interface. It creates the WritableStream with a custom sink. It then calls the stream's getWriter() method, which returns an instance of WritableStreamDefaultWriter. Next, several strings are written to the stream. Finally, close() returns a promise that resolves when all the writes have successfully completed.
js
const writableStream = new WritableStream(
// Implement the sink
{
write(chunk) {
const textElement = document.getElementById("text-output");
textElement.textContent += chunk;
},
},
);
const writer = writableStream.getWriter();
try {
writer.write("Hello, ");
writer.write("world!\n");
writer.write("This has been a demo!\n");
await writer.close(); // wait for all chunks to be written
console.log("All chunks written");
} catch (error) {
console.error("Stream error: ", error);
}
This example does not support the backpressure feature of Streams.
