js

close()

js

function sendMessage(message, writableStream) {
  // defaultWriter is of type WritableStreamDefaultWriter
  const defaultWriter = writableStream.getWriter();
  const encoder = new TextEncoder();
  const encoded = encoder.encode(message, { stream: true });
  encoded.forEach((chunk) => {
    defaultWriter.ready
      .then(() => {
        defaultWriter.write(chunk);
      })
      .catch((err) => {
        log("Chunk error:", err);
      });
  });

  // Call ready again to ensure that all chunks are written
  //   before closing the writer.
  defaultWriter.ready
    .then(() => {
      defaultWriter.releaseLock();
      writableStream.close();
    })
    .then(() => {
      log("All chunks written / stream closed.");
    })
    .catch((err) => {
      log("Stream error:", err);
    });
}

const decoder = new TextDecoder("utf-8");
const queuingStrategy = new CountQueuingStrategy({ highWaterMark: 1 });
let result = "";
const writableStream = new WritableStream(
  {
    // Implement the sink
    write(chunk) {
      return new Promise((resolve, reject) => {
        const buffer = new ArrayBuffer(1);
        const view = new Uint8Array(buffer);
        view[0] = chunk;
        const decoded = decoder.decode(view, { stream: true });
        const listItem = document.createElement("li");
        result += decoded;
        resolve();
      });
    },
    close() {
      const listItem = document.createElement("li");
      log(`[MESSAGE RECEIVED] ${result}`);
    },
    abort(err) {
      log("Sink error:", err);
    },
  },
  queuingStrategy,
);

log("Sending 'Hello, world.' message.");
sendMessage("Hello, world.", writableStream);