sync-middlware.js

/**
 *  Creates a redux middleware which will send every action over a websocket connection.
 *  @param  {WebSocket} socket The websocket connection object
 *  @return {Function}  A redux middleware function
 */
function createSyncMiddleware(socket) {
  return () => next => action => {
    // your actions should not contain any functions, which can´t be stringified
    socket.send(JSON.stringify(action));
    // don´t forget this otherwise the middleware will swallow all actions
    next(action);
  }
}