feat: expose Web SDK streaming APIs and describeImage in wrapper libraries

libraries/API_PARITY.md

@@ -0,0 +1,79 @@
+# API Parity Reference
+
+Cross-platform availability matrix for Locanara wrapper libraries.
+
+## Core AI Features
+
+| API | expo-ondevice-ai | react-native-ondevice-ai | flutter_ondevice_ai | Notes |
+| --- | :---: | :---: | :---: | --- |
+| `initialize()` | ✅ | ✅ | ✅ | |
+| `getDeviceCapability()` | ✅ | ✅ | ✅ | |
+| `summarize(text, options?)` | ✅ | ✅ | ✅ | |
+| `classify(text, options?)` | ✅ | ✅ | ✅ | |
+| `extract(text, options?)` | ✅ | ✅ | ✅ | |
+| `chat(message, options?)` | ✅ | ✅ | ✅ | |
+| `chatStream(message, options?)` | ✅ | ✅ | ✅ | Streaming via `onChunk` callback |
+| `translate(text, options)` | ✅ | ✅ | ✅ | |
+| `rewrite(text, options)` | ✅ | ✅ | ✅ | |
+| `proofread(text, options?)` | ✅ | ✅ | ✅ | |
+
+## Streaming Variants
+
+Streaming is supported for all text-generation features via callback-based APIs. Each
+streaming function accepts an `onChunk` callback that delivers tokens progressively.
+
+| API | expo-ondevice-ai | react-native-ondevice-ai | flutter_ondevice_ai | Notes |
+| --- | :---: | :---: | :---: | --- |
+| `summarizeStreaming(text, options?)` | ✅ | ✅ | 🚧 | `onChunk` callback |
+| `translateStreaming(text, options)` | ✅ | ✅ | 🚧 | `onChunk` callback |
+| `rewriteStreaming(text, options)` | ✅ | ✅ | 🚧 | `onChunk` callback |
+| `chatStream(message, options?)` | ✅ | ✅ | ✅ | Already supported |
+
+## Image Features
+
+| API | expo-ondevice-ai | react-native-ondevice-ai | flutter_ondevice_ai | Notes |
+| --- | :---: | :---: | :---: | --- |
+| `describeImage(imageUri, options?)` | ✅ | ✅ | 🚧 | iOS (Foundation Models Vision) + Android (describeImageAndroid) |
+| `describeImageStreaming(imageUri, options?)` | 🚧 | 🚧 | 🚧 | Planned |
+
+## Chrome-Only Features
+
+These APIs are available exclusively in the **Web SDK** (`@locanara/web`) because they
+rely on Chrome's Built-in AI APIs. They are **not available** in Expo, React Native, or
+Flutter wrapper libraries.
+
+| API | Web SDK | Wrappers | Reason |
+| --- | :---: | :---: | --- |
+| `detectLanguage(text)` | ✅ | ❌ | Chrome Language Detection API only |
+| `write(prompt, options?)` | ✅ | ❌ | Chrome Writer API only |
+| `writeStreaming(prompt, options?)` | ✅ | ❌ | Chrome Writer API only |
+
+If you need language detection on mobile, consider using a third-party library like
+`react-native-mlkit` or the device's built-in locale detection.
+
+## Model Management
+
+| API | expo-ondevice-ai | react-native-ondevice-ai | flutter_ondevice_ai | Notes |
+| --- | :---: | :---: | :---: | --- |
+| `getAvailableModels()` | ✅ | ✅ | ✅ | iOS only — returns `[]` on Android |
+| `getDownloadedModels()` | ✅ | ✅ | ✅ | iOS only — returns `[]` on Android |
+| `getLoadedModel()` | ✅ | ✅ | ✅ | |
+| `getCurrentEngine()` | ✅ | ✅ | ✅ | |
+| `downloadModel(id, onProgress?)` | ✅ | ✅ | ✅ | iOS only |
+| `loadModel(id)` | ✅ | ✅ | ✅ | iOS only |
+| `deleteModel(id)` | ✅ | ✅ | ✅ | iOS only |
+
+## Android-Only Features
+
+| API | expo-ondevice-ai | react-native-ondevice-ai | flutter_ondevice_ai | Notes |
+| --- | :---: | :---: | :---: | --- |
+| `getPromptApiStatus()` | ✅ | ✅ | ✅ | Android only — Gemini Nano Prompt API status |
+| `downloadPromptApiModel(onProgress?)` | ✅ | ✅ | ✅ | Android only — download Gemini Nano |
+
+## Legend
+
+| Symbol | Meaning |
+| --- | --- |
+| ✅ | Available |
+| 🚧 | Planned / In Progress |
+| ❌ | Not available on this platform |

libraries/expo-ondevice-ai/src/index.ts

@@ -4,6 +4,7 @@ import type {
   DeviceCapability,
   SummarizeOptions,
   SummarizeResult,
+  SummarizeStreamOptions,
   ClassifyOptions,
   ClassifyResult,
   ExtractOptions,
@@ -12,16 +13,21 @@ import type {
   ChatResult,
   ChatStreamChunk,
   ChatStreamOptions,
+  TextStreamChunk,
   TranslateOptions,
   TranslateResult,
+  TranslateStreamOptions,
   RewriteOptions,
   RewriteResult,
+  RewriteStreamOptions,
   ProofreadOptions,
   ProofreadResult,
   InitializeResult,
   DownloadableModelInfo,
   ModelDownloadProgress,
   InferenceEngine,
+  DescribeImageOptions,
+  DescribeImageResult,
 } from './types';
 import {ExpoOndeviceAiLog as Log} from './log';
 
@@ -172,6 +178,140 @@ export async function proofread(
   return ExpoOndeviceAiModule.proofread(text, options);
 }
 
+// MARK: - Streaming Variants
+
+/**
+ * Summarize text with streaming — tokens delivered progressively via onChunk.
+ * @param text - The text to summarize
+ * @param options - Options including onChunk callback
+ * @returns Promise resolving to final SummarizeResult
+ */
+export async function summarizeStreaming(
+  text: string,
+  options?: SummarizeStreamOptions,
+): Promise<SummarizeResult> {
+  let subscription: EventSubscription | undefined;
+
+  try {
+    if (options?.onChunk) {
+      subscription = (
+        ExpoOndeviceAiModule as unknown as {
+          addListener: (
+            name: string,
+            listener: (chunk: TextStreamChunk) => void,
+          ) => EventSubscription;
+        }
+      ).addListener('onSummarizeStreamChunk', (chunk: TextStreamChunk) => {
+        options.onChunk!(chunk);
+      });
+    }
+
+    const {onChunk: _, ...nativeOptions} = options ?? {};
+    const result: SummarizeResult = await ExpoOndeviceAiModule.summarizeStreaming(
+      text,
+      Object.keys(nativeOptions).length > 0 ? nativeOptions : undefined,
+    );
+
+    await new Promise<void>((resolve) => setTimeout(resolve, 0));
+    return result;
+  } finally {
+    subscription?.remove();
+  }
+}
+
+/**
+ * Translate text with streaming — tokens delivered progressively via onChunk.
+ * @param text - The text to translate
+ * @param options - Options including targetLanguage and onChunk callback
+ * @returns Promise resolving to final TranslateResult
+ */
+export async function translateStreaming(
+  text: string,
+  options: TranslateStreamOptions,
+): Promise<TranslateResult> {
+  let subscription: EventSubscription | undefined;
+
+  try {
+    if (options.onChunk) {
+      subscription = (
+        ExpoOndeviceAiModule as unknown as {
+          addListener: (
+            name: string,
+            listener: (chunk: TextStreamChunk) => void,
+          ) => EventSubscription;
+        }
+      ).addListener('onTranslateStreamChunk', (chunk: TextStreamChunk) => {
+        options.onChunk!(chunk);
+      });
+    }
+
+    const {onChunk: _, ...nativeOptions} = options;
+    const result: TranslateResult = await ExpoOndeviceAiModule.translateStreaming(
+      text,
+      nativeOptions,
+    );
+
+    await new Promise<void>((resolve) => setTimeout(resolve, 0));
+    return result;
+  } finally {
+    subscription?.remove();
+  }
+}
+
+/**
+ * Rewrite text with streaming — tokens delivered progressively via onChunk.
+ * @param text - The text to rewrite
+ * @param options - Options including outputType and onChunk callback
+ * @returns Promise resolving to final RewriteResult
+ */
+export async function rewriteStreaming(
+  text: string,
+  options: RewriteStreamOptions,
+): Promise<RewriteResult> {
+  let subscription: EventSubscription | undefined;
+
+  try {
+    if (options.onChunk) {
+      subscription = (
+        ExpoOndeviceAiModule as unknown as {
+          addListener: (
+            name: string,
+            listener: (chunk: TextStreamChunk) => void,
+          ) => EventSubscription;
+        }
+      ).addListener('onRewriteStreamChunk', (chunk: TextStreamChunk) => {
+        options.onChunk!(chunk);
+      });
+    }
+
+    const {onChunk: _, ...nativeOptions} = options;
+    const result: RewriteResult = await ExpoOndeviceAiModule.rewriteStreaming(
+      text,
+      nativeOptions,
+    );
+
+    await new Promise<void>((resolve) => setTimeout(resolve, 0));
+    return result;
+  } finally {
+    subscription?.remove();
+  }
+}
+
+// MARK: - Image Description
+
+/**
+ * Describe the contents of an image using on-device AI.
+ * Supported on iOS (Foundation Models Vision API) and Android.
+ * @param imageUri - URI or file path to the image
+ * @param options - Optional prompt and other options
+ */
+export async function describeImage(
+  imageUri: string,
+  options?: DescribeImageOptions,
+): Promise<DescribeImageResult> {
+  return ExpoOndeviceAiModule.describeImage(imageUri, options);
+}
+
 // MARK: - Model Management
 
 /**

libraries/expo-ondevice-ai/src/types.ts

@@ -200,6 +200,62 @@ export interface ChatStreamOptions extends ChatOptions {
   onChunk?: (chunk: ChatStreamChunk) => void;
 }
 
+/**
+ * A single streamed chunk for summarize / translate / rewrite streaming
+ */
+export interface TextStreamChunk {
+  /** New text delta in this chunk */
+  delta: string;
+  /** Full accumulated text so far */
+  accumulated: string;
+  /** Whether this is the final chunk */
+  isFinal: boolean;
+}
+
+/**
+ * Options for streaming summarization
+ */
+export interface SummarizeStreamOptions extends SummarizeOptions {
+  /** Callback invoked for each streamed token */
+  onChunk?: (chunk: TextStreamChunk) => void;
+}
+
+/**
+ * Options for streaming translation
+ */
+export interface TranslateStreamOptions extends TranslateOptions {
+  /** Callback invoked for each streamed token */
+  onChunk?: (chunk: TextStreamChunk) => void;
+}
+
+/**
+ * Options for streaming rewrite
+ */
+export interface RewriteStreamOptions extends RewriteOptions {
+  /** Callback invoked for each streamed token */
+  onChunk?: (chunk: TextStreamChunk) => void;
+}
+
+// MARK: - Image Description
+
+/**
+ * Options for image description
+ */
+export interface DescribeImageOptions {
+  /** Optional prompt to guide the description */
+  prompt?: string;
+}
+
+/**
+ * Result of image description
+ */
+export interface DescribeImageResult {
+  /** The generated description */
+  description: string;
+  /** Confidence score (0-1) */
+  confidence?: number;
+}
+
 /**
  * Options for translation
  */