feat(error-handler): add error handler middleware POC

app/redux/errorHandler.js

@@ -0,0 +1,22 @@
+// @flow
+import { LOAD_ADDRESSES_ERROR } from './modules/receive';
+import { VALIDATE_ADDRESS_ERROR } from './modules/send';
+import { LOAD_TRANSACTIONS_ERROR } from './modules/transactions';
+import { LOAD_WALLET_SUMMARY_ERROR } from './modules/wallet';
+import { showErrorModal } from './modules/app';
+
+import type { Middleware } from '../types/redux';
+
+const ERRORS = [
+  LOAD_ADDRESSES_ERROR,
+  VALIDATE_ADDRESS_ERROR,
+  LOAD_TRANSACTIONS_ERROR,
+  LOAD_WALLET_SUMMARY_ERROR,
+];
+
+export const errorHandler: Middleware = ({ dispatch }) => next => (action) => {
+  // eslint-disable-next-line max-len
+  if (ERRORS.includes(action.type)) return dispatch(showErrorModal({ error: action.payload.error || 'Something went wrong!' }));
+
+  return next(action);
+};