CrashReporter.js

import { Client, Configuration } from 'bugsnag-react-native';

module.exports = {  // cached singleton instance


  instance: null,
  
  create(key, store, codeBundleId) {
    if (this.instance === null) {
      if (key == null) {
        throw new Error(`Crash Reporter should be created with a
         key as the first param. i.e .create(key, reduxStore)`);
      }
      
      const bugsnagConfig = new Configuration(key);

      bugsnagConfig.shouldNotify = () => !__DEV__;
      
      // code bundle id
      if (codeBundleId) {
        bugsnagConfig.codeBundleId = codeBundleId;
      }
      
      bugsnagConfig.notifyReleaseStages = ['production', 'staging', 'testflight'];
      
      bugsnagConfig.registerBeforeSendCallback((report) => {
        const state = JSON.parse(JSON.stringify(store.getState()));
        const metadata = report.metadata || {};
        
        // add our calendar state as metadata
        metadata.calendar = state.calendar;
        
        if (metadata.app == null) {
          metadata.app = {};
        }
        
        // if the codebundleid is null, add it to the metadata
        if (metadata.app.codeBundleId == null) {
          metadata.app.codeBundleId = codeBundleId;
        }
        
        report.metadata = metadata;
      });
      
      this.instance = new Client(bugsnagConfig);
    }
    return this.instance;
  },

};

index.js

CrashReporter.create(CONFIG.BUGSNAG_KEY, store, curAppVersion);