convertToPlainObjectMiddleware.js

import { Middleware, Action } from 'redux';

// Grabbed from:
// https://github.com/reactjs/redux/blob/master/src/utils/isPlainObject.js
function isPlainObject(obj: any) {
  if (typeof obj !== 'object' || obj === null) return false

  let proto = obj
  while (Object.getPrototypeOf(proto) !== null) {
    proto = Object.getPrototypeOf(proto)
  }

  return Object.getPrototypeOf(obj) === proto
}

// Workaround for:
// https://github.com/reactjs/redux/issues/2361
const convertToPlainObject: Middleware = store => next => (action: any) => {
  if (!isPlainObject(action) && typeof action === 'object') {
    return Object.assign({}, action);
  }
}