Migration Guide - React Native Sherpa-ONNX

This guide helps you migrate from version 0.2.x to 0.3.0 of react-native-sherpa-onnx. Version 0.3.0 introduces significant improvements including full iOS support, better performance, and ~95% size reduction, but requires code changes.

Overview

Version 0.3.0 introduces:

Instance-based API (TTS + STT)
Improved return types and type safety
Model-specific options structure
Renamed types and methods

Breaking Changes: This release changes the public API. Please follow all migration steps before upgrading.

Instance-based API (TTS + STT)

Understanding the Change

TTS and STT now use an instance-based factory pattern instead of module-level singletons. Each call to createTTS() / createSTT() returns an independent engine instance.Key requirement: You must call .destroy() when done to free native resources.

Migrate TTS Code

Before (0.2.x):

initializeTTS({ modelPath: { type: 'asset', path: 'models/vits' } });
const audio = await generateSpeech('Hello');
await unloadTTS();

After (0.3.0):

const tts = await createTTS({ modelPath: { type: 'asset', path: 'models/vits' } });
const audio = await tts.generateSpeech('Hello');
await tts.destroy();

Migrate STT Code

Before (0.2.x):

await initializeSTT({ modelPath: { type: 'asset', path: 'models/whisper' } });
const result = await transcribeFile('/audio.wav');
await unloadSTT();

After (0.3.0):

const stt = await createSTT({ modelPath: { type: 'asset', path: 'models/whisper' } });
const result = await stt.transcribeFile('/audio.wav');
await stt.destroy();

Speech-to-Text (STT) Changes

Return Type Changes

transcribeFile now returns a detailed object instead of just a string:

- const text: string = await transcribeFile(path);
+ const result: SttRecognitionResult = await stt.transcribeFile(path);
+ const text = result.text;

New return type structure:

interface SttRecognitionResult {
  text: string;           // Transcribed text
  tokens: string[];       // Token sequence
  timestamps: number[];   // Timestamp per token
  lang: string;          // Detected language (if supported)
  emotion: string;       // Emotion tag (if supported)
  event: string;         // Event tag (if supported)
  durations: number[];   // Duration info
}

If you only need the text, use result.text to get the transcription string.

Hotwords Support

initializeSTT now supports two additional optional options:

await createSTT({
  modelPath: { type: 'asset', path: 'models/whisper' },
  hotwordsFile: '/path/to/hotwords.txt',  // NEW
  hotwordsScore: 1.5,                      // NEW
});

Deprecated Types

- TranscriptionResult  // REMOVED
+ SttRecognitionResult  // Use this instead

Native Method Renames

If you call the TurboModule directly, methods were renamed:

- initializeSherpaOnnx
+ initializeStt

- unloadSherpaOnnx
+ unloadStt

Text-to-Speech (TTS) Changes

Model Options Structure

Model-specific options (noise scales, length scale) now use a nested modelOptions structure instead of flat properties.

initializeTTS({
  modelPath: { type: 'asset', path: 'models/vits' },
  modelType: 'vits',
  noiseScale: 0.667,
  noiseScaleW: 0.8,
  lengthScale: 1.0
});

const tts = await createTTS({
  modelPath: { type: 'asset', path: 'models/vits' },
  modelType: 'vits',
  modelOptions: {
    vits: {
      noiseScale: 0.667,
      noiseScaleW: 0.8,
      lengthScale: 1.0
    }
  }
});

Update Parameters

The updateParams method also uses the new structure:

updateTtsParams({
  noiseScale: 0.7,
  lengthScale: 1.2
});

tts.updateParams({
  modelOptions: {
    vits: {
      noiseScale: 0.7,
      lengthScale: 1.2
    }
  }
});

New Model-Specific Types

The following types are now exported:

import type {
  TtsModelOptions,
  TtsVitsModelOptions,
  TtsMatchaModelOptions,
  TtsKokoroModelOptions,
  TtsKittenModelOptions,
  TtsPocketModelOptions
} from 'react-native-sherpa-onnx/tts';

Instance Methods and TurboModule

If you call the TurboModule directly, all instance-bound methods now take instanceId as the first parameter:

// Instance methods
tts.generateSpeech(text)      // High-level API
tts.generateSpeechStream()     // High-level API
tts.destroy()                  // High-level API

// Direct TurboModule (advanced)
module.generateSpeech(instanceId, text)  // Low-level

Deprecated Types

- SynthesisOptions    // REMOVED
+ TtsGenerationOptions // Use this instead

Complete Migration Example

STT Migration
TTS Migration

Before (0.2.x):

import { initializeSTT, transcribeFile, unloadSTT } from 'react-native-sherpa-onnx/stt';

async function transcribeAudio(audioPath: string) {
  await initializeSTT({
    modelPath: { type: 'asset', path: 'models/whisper-tiny' },
    modelType: 'whisper'
  });
  
  const text = await transcribeFile(audioPath);
  console.log('Transcription:', text);
  
  await unloadSTT();
  return text;
}

After (0.3.0):

import { createSTT } from 'react-native-sherpa-onnx/stt';

async function transcribeAudio(audioPath: string) {
  const stt = await createSTT({
    modelPath: { type: 'asset', path: 'models/whisper-tiny' },
    modelType: 'whisper'
  });
  
  try {
    const result = await stt.transcribeFile(audioPath);
    console.log('Transcription:', result.text);
    console.log('Language:', result.lang);
    return result.text;
  } finally {
    await stt.destroy(); // Always cleanup
  }
}

Before (0.2.x):

import { initializeTTS, generateSpeech, unloadTTS } from 'react-native-sherpa-onnx/tts';

async function speakText(text: string) {
  await initializeTTS({
    modelPath: { type: 'asset', path: 'models/vits-piper' },
    modelType: 'vits',
    noiseScale: 0.667,
    lengthScale: 1.0
  });
  
  const audio = await generateSpeech(text);
  // Play audio...
  
  await unloadTTS();
}

After (0.3.0):

import { createTTS } from 'react-native-sherpa-onnx/tts';

async function speakText(text: string) {
  const tts = await createTTS({
    modelPath: { type: 'asset', path: 'models/vits-piper' },
    modelType: 'vits',
    modelOptions: {
      vits: {
        noiseScale: 0.667,
        lengthScale: 1.0
      }
    }
  });
  
  try {
    const audio = await tts.generateSpeech(text);
    // Play audio...
  } finally {
    await tts.destroy(); // Always cleanup
  }
}

Common Patterns

Managing Multiple Instances

import { createSTT, createTTS } from 'react-native-sherpa-onnx';

class SpeechManager {
  private stt: SttEngine | null = null;
  private tts: TtsEngine | null = null;

  async initialize() {
    this.stt = await createSTT({
      modelPath: { type: 'asset', path: 'models/whisper' },
      modelType: 'auto'
    });

    this.tts = await createTTS({
      modelPath: { type: 'asset', path: 'models/vits' },
      modelType: 'auto'
    });
  }

  async cleanup() {
    if (this.stt) {
      await this.stt.destroy();
      this.stt = null;
    }
    if (this.tts) {
      await this.tts.destroy();
      this.tts = null;
    }
  }
}

React Hook Pattern

import { useEffect, useRef } from 'react';
import { createSTT } from 'react-native-sherpa-onnx/stt';

function useSpeechRecognition() {
  const sttRef = useRef<SttEngine | null>(null);

  useEffect(() => {
    let mounted = true;

    async function init() {
      const stt = await createSTT({
        modelPath: { type: 'asset', path: 'models/whisper' },
        modelType: 'auto'
      });
      
      if (mounted) {
        sttRef.current = stt;
      } else {
        await stt.destroy();
      }
    }

    init();

    return () => {
      mounted = false;
      if (sttRef.current) {
        sttRef.current.destroy();
      }
    };
  }, []);

  return sttRef.current;
}

Need Help?

If you encounter issues during migration:

Check the API Reference for detailed method signatures
Review Troubleshooting for common issues
See Examples for working code samples
Open an issue on GitHub

​Overview

​Instance-based API (TTS + STT)

​Speech-to-Text (STT) Changes

​Return Type Changes

​Hotwords Support

​Deprecated Types

​Native Method Renames

​Text-to-Speech (TTS) Changes

​Model Options Structure

​Update Parameters

​New Model-Specific Types

​Instance Methods and TurboModule

​Deprecated Types

​Complete Migration Example

​Common Patterns

​Managing Multiple Instances

​React Hook Pattern

​Need Help?

Overview

Instance-based API (TTS + STT)

Speech-to-Text (STT) Changes

Return Type Changes

Hotwords Support

Deprecated Types

Native Method Renames

Text-to-Speech (TTS) Changes

Model Options Structure

Update Parameters

New Model-Specific Types

Instance Methods and TurboModule

Deprecated Types

Complete Migration Example

Common Patterns

Managing Multiple Instances

React Hook Pattern

Need Help?