react-native-ocr-package/index.js

A React component for scanning National Identity cards using a device's camera. This package integrates OCR technology to extract the text data from scanned cards by making API calls.

import CameraComponent from './src/components/CameraComponent';
import LivenessDetection from './src/components/LivenessDetection';
import { Platform, NativeModules, InteractionManager, BackHandler } from 'react-native';

/**
 * Utility function to manage the workflow between liveness detection and document scanning
 * @param {Object} options Configuration options
 * @param {string} options.ocrApiUrl The API endpoint for OCR processing
 * @param {Function} options.onError Callback for any errors during the process
 * @param {boolean} options.skipLiveness Optional flag to skip liveness and go directly to document scanning
 * @returns {Object} An object with control methods
 */
const VerificationWorkflow = {
  // Track if we're currently in a transition
  _isTransitioning: false,
  
  /**
   * Start the verification process with liveness detection first
   */
  startVerification: (options) => {
    const { 
      ocrApiUrl, 
      onError,
      skipLiveness = false,
      transitionDelay = 3000, // Further increased delay to ensure stability
    } = options || {};
    
    // Reset transition flag
    VerificationWorkflow._isTransitioning = false;
    
    if (!ocrApiUrl) {
      if (onError) onError(new Error('OCR API URL is required'));
      return;
    }
    
    // Store for later use in the document scan
    let livenessResult = null;
    
    // Add an event listener to handle back button during transition (Android only)
    const backHandler = Platform.OS === 'android' ? 
      BackHandler.addEventListener('hardwareBackPress', () => {
        // During transitions, prevent going back to avoid restart issues
        if (VerificationWorkflow._isTransitioning) {
          return true; // Prevent default behavior
        }
        return false;
      }) : null;
    
    const proceedToDocumentScan = () => {
      // Prevent duplicate transitions
      if (VerificationWorkflow._isTransitioning) return;
      
      VerificationWorkflow._isTransitioning = true;
      
      // Ensure any native UI animations have completed
      InteractionManager.runAfterInteractions(() => {
        // Add a delay to allow native resources to clean up
        setTimeout(() => {
          // Remove the back handler when we're ready to proceed
          if (backHandler) {
            backHandler.remove();
          }
          
          VerificationWorkflow._isTransitioning = false;
          
          // Notify caller that it's ready for document scanning
          // Run this on the next frame to ensure the UI is ready
          requestAnimationFrame(() => {
            if (options.onReadyForDocumentScan) {
              options.onReadyForDocumentScan(livenessResult);
            }
          });
        }, transitionDelay);
      });
    };
    
    // Skip liveness check if requested or not on Android
    if (skipLiveness || Platform.OS !== 'android') {
      proceedToDocumentScan();
      return;
    }
    
    try {
      // Quick platform check
      if (Platform.OS !== 'android') {
        proceedToDocumentScan();
        return;
      }
      
      // Start liveness detection with a wrapped promise to ensure proper handling
      const startLiveness = async () => {
        try {
          const isAvailable = await LivenessDetection.isAvailable();
          
          if (!isAvailable) {
            proceedToDocumentScan();
            return;
          }
          
          // Start liveness detection and capture result
          const result = await LivenessDetection.startLivenessDetection();
          
          if (!result) {
            proceedToDocumentScan();
            return;
          }
          
          // Store liveness result and proceed
          livenessResult = result;
          
          // Clean up before proceeding
          InteractionManager.runAfterInteractions(() => {
            proceedToDocumentScan();
          });
        } catch (err) {
          if (onError) onError(err);
          
          // Still proceed to document scanning despite errors
          setTimeout(() => {
            proceedToDocumentScan();
          }, 1000);
        }
      };
      
      // Start the liveness flow
      startLiveness();
    } catch (error) {
      if (onError) onError(error);
      
      // Proceed to document scanning despite error
      setTimeout(() => {
        proceedToDocumentScan();
      }, 1000);
    }
  },
  
  /**
   * Combines liveness and OCR results into a single result object
   */
  combineResults: (livenessResult, ocrResult) => {
    // Simple combination with no unnecessary structuring
    return {
      liveness: livenessResult || null,
      ocr: ocrResult || null
    };
  }
};

export { CameraComponent, LivenessDetection, VerificationWorkflow };