Redux exception logging with Raygun4JS

errorReportingMiddleware.js

const errorReportingMiddleware = store => next => action => {
  try {
    return next(action);
  } catch(err) {
    console.error('Caught an exception!', err);

    window.rg4js('send', {
      error: err,
      customData: {
        action,
        state: store.getState()
      }
    });
  }
};

export default errorReportingMiddleware;

store.js

import { createStore, applyMiddleware } from 'redux';
import errorReportingMiddleware from './errorReportingMiddleware';

function App(state = 0, action) {
  // Simulate an error
  if (state === 5)
    null.bar

  switch(action.type) {
    case 'increment':
      return state + 1;
    case 'decrement':
      return state - 1;
  }

  return state;
}

// Targeted approach, only attach Redux state to errors that happen during Redux actions 
// Create the store, including the crashReportingMiddleware
const store = createStore(App, applyMiddleware(crashReportingMiddleware));

// Global approach, attach Redux state to any error that occurs on the page
// Attach a global Raygun4JS custom data handler
window.rg4js('withCustomData', () => {
  const state = store.getState();

  return { state };
});

export default store;