index.js

import React, { Component } from 'react';
import {
  requireNativeComponent,
  NativeModules,
  View,
  TouchableHighlight
} from 'react-native';
import PropTypes from 'prop-types';

const scannerModule = NativeModules['BarcodeScannerModule'];

const BARCODE_FOUND_KEY = 'barcode_found';
const LOW_STORAGE_EXCEPTION = 'low_storage';
const NOT_YET_OPERATIONAL_EXCEPTION = 'not_yet_operational';
const NO_PLAY_SERVICES_EXCEPTION = 'no_play_services';

class BarcodeScanner extends Component {
  static propTypes = {
    onBarcodeRead: PropTypes.func, // Callback that fires whenever a new barcode is read
    onBarCodeRead: PropTypes.func, // alias of onBarcodeRead (for compatibility with other libraries)
    onException: PropTypes.func, // function(reason)
    barcodeTypes: PropTypes.number, // int
    focusMode: PropTypes.number, // int
    torchMode: PropTypes.number, // int
    cameraFillMode: PropTypes.number, // int
    ...View.propTypes
  };

  componentWillMount() {
    resumeScanner()
      .then(() => {
        console.log('BarcodeScanner was resumed on component mount.');
      })
      .catch(e => {
        // In regular usage this 'exception' is harmless, so we just log it instead of warning the user (dev).
        console.log(e);
      });
  }

  componentWillUnmount() {
    pauseScanner()
      .then(() => {
        console.log('BarcodeScanner was paused on component mount.');
      })
      .catch(e => {
        // In regular usage this 'exception' is harmless, so we just log it instead of warning the user (dev).
        console.log(e);
      });
  }

  _onChange(event: Event) {
    switch (event.nativeEvent.key) {
      case BARCODE_FOUND_KEY:
        const onBarcodeRead =
          this.props.onBarcodeRead || this.props.onBarCodeRead;
        if (onBarcodeRead) {
          onBarcodeRead({
            data: event.nativeEvent.data, // the barcode itself
            type: event.nativeEvent.type // the barcode type, eg "EAN_13"
          });
        }
        break;
      case NOT_YET_OPERATIONAL_EXCEPTION:
      case LOW_STORAGE_EXCEPTION:
      case NO_PLAY_SERVICES_EXCEPTION:
        if (this.props.onException)
          this.props.onException(event.nativeEvent.key);
        break;
    }
  }

  render() {
    return (
      <NativeBarcodeScanner
        {...this.props}
        onChange={this._onChange.bind(this)}
      />
    );
  }
}

const NativeBarcodeScanner = requireNativeComponent(
  'RCTBarcodeScannerManager',
  BarcodeScanner,
  {
    nativeOnly: { onChange: true }
  }
);

/* --------------------------------------
 * ------------- Exports ----------------
 * --------------------------------------
 */

// Alternatives: ALL, CODE_128, CODE_39, CODE_93, CODABAR, DATA_MATRIX, EAN_13, EAN_8, ITF, QR_CODE, UPC_A, UPC_E, PDF417, AZTEC
export const BarcodeType = scannerModule.BarcodeType;
// Alternatives: AUTO, TAP, FIXED. Note: focusMode TAP won't work if you place a view on top of BarcodeScanner, that catches all touch events.
export const FocusMode = scannerModule.FocusMode;
// Alternatives: OFF, ON
export const TorchMode = scannerModule.TorchMode;
// Alternatives: COVER, FIT
export const CameraFillMode = scannerModule.CameraFillMode;

export const Exception = {
  LOW_STORAGE: LOW_STORAGE_EXCEPTION,
  NOT_OPERATIONAL: NOT_YET_OPERATIONAL_EXCEPTION,
  NO_PLAY_SERVICES: NO_PLAY_SERVICES_EXCEPTION
};

// Methods that the user (dev) might access to pause/resume the scanner at will
export const pauseScanner = scannerModule.pause;
export const resumeScanner = scannerModule.resume;

export default BarcodeScanner;