Writer API

if ('Writer' in self) {
  // The Writer API is supported.
}

const availability = await Writer.availability();

const writer = await Writer.create({
  monitor(m) {
    m.addEventListener("downloadprogress", e => {
      console.log(`Downloaded ${e.loaded * 100}%`);
    });
  }
});

const options = {
  sharedContext: 'This is an email to acquaintances about an upcoming event.',
  tone: 'casual',
  format: 'plain-text',
  length: 'medium',
};

const available = await Writer.availability();
let writer;
if (available === 'unavailable') {
  // The Writer API isn't usable.
  return;
}
if (available === 'available') {
  // The Writer API can be used immediately .
  writer = await Writer.create(options);
} else {
  // The Writer can be used after the model is downloaded.
  const writer = await Writer.create({
    ...options,
    monitor(m) {
      m.addEventListener("downloadprogress", e => {
        console.log(`Downloaded ${e.loaded * 100}%`);
      });
    }
  });
}

const writer = await Writer.create({
  tone: "formal",
  expectedInputLanguages: ["en", "ja", "es"],
  expectedContextLanguages: ["en", "ja", "es"],
  outputLanguage: "es",
  sharedContext: "These are requests to write messages to teachers in a Spanish
    language program, by students who may speak Spanish, Japanese, or English.
    Staff expect questions to be written in Spanish."
});

// Request-based
const writer = await Writer.create();
const result = await writer.write(
  "An inquiry to my bank about how to enable wire transfers on my account.",
  {
    context: "I'm a longstanding customer",
  },
);

// Streaming
const writer = await Writer.create(
  expectedInputLanguages: ["en"],
  expectedContextLanguages: ["en"],
  outputLanguage: "en",
);
const stream = writer.writeStreaming(
  "An inquiry to my bank about how to enable wire transfers on my account.", {
    context: "I'm a longstanding customer",
  },
);
for await (const chunk of stream) {
  composeTextbox.append(chunk);
}

// Shared context and per writing task context
const writer = await Writer.create({
    expectedInputLanguages: ["en"],
    expectedContextLanguages: ["en"],
    outputLanguage: "en",
    sharedContext:
      "This is for publishing on [popular website name], a business" +
      "and employment-focused social media platform."
});

const stream = writer.writeStreaming(
  "Write a blog post about how I love all this work on gen AI at Google!" +
  "Mention that there's so much to learn and so many new things I can do!",
  { context: " The request comes from someone working at a startup providing an e-commerce CMS solution."}
);

for await (const chunk of stream) {
  composeTextbox.append(chunk);
}

// Reuse a writer
const writer = await Writer.create({ tone: "formal" });

const reviews = await Promise.all(
  Array.from(
    document.querySelectorAll("#reviews > .review"),
    (reviewEl) => writer.write(reviewEl.textContent)
  ),
);

// Aborting a writer
const controller = new AbortController();
stopButton.onclick = () => controller.abort();

const writer = await Writer.create({ signal: controller.signal });
await writer.write(reviewEl.textContent, { signal: controller.signal });

// Destroying a writer
writer.destroy();

<!--
  The hosting site at https://main.example.com can grant a cross-origin iframe
  at https://cross-origin.example.com/ access to the Writer API by
  setting the `allow="writer"` attribute.
-->
<iframe src="https://cross-origin.example.com/" allow="writer"></iframe>