jacobp100

const subscribeMiddleware = () => store => {
  let handlers = [];

  store.subscribe = (cb) => {
    handlers = handlers.concat(cb);
    const removeSubscriber = () => { handlers = handlers.filter(fn => fn !== cb) };
    return removeSubscriber;
  };

  return next => (action) => {

jacobp100

const createStore = ({
  reducer = state => state,
  middlewares = [],
  initialState = undefined,
}) => {
  const store = {};

  store.dispatch = combineMiddlewares([
    ...middlewares,
    reducerMiddleware(reducer, initialState)

jacobp100

const reducerMiddleware = (reducer, initialState) => store => {
  let state = initialState;

  store.getState = () => state;

  return () => (action) => { state = reducer(state, action); };
};

jacobp100

const createStore = ({ middlewares = [] }) => {
  const store = {};

  store.dispatch = combineMiddlewares(middlewares)(store);

  return store;
};

jacobp100

const combineMiddlewares = middlewares => (store) => {
  const propagationFunctions = middlewares.map(middleware => (
    middleware(store)
  ));
  const invokeMiddlewareChain = propagationFunctions.reduceRight((nextFn, propagationFunction) => (
    propagationFunction(nextFn)
  ), null);
  return invokeMiddlewareChain;
};

jacobp100

const middleware = () => store => next => action => {
  // Get the state before and after the action was performed
  const previousToken = store.getState().token;
  next(action);
  const nextToken = store.getState().token;

  // Respond to changes
  if (nextToken !== previousToken) localStorage.setItem('token', nextToken);
};

jacobp100

const middleware = musicPlayer => store => {
  const playbackOrigin = 'playbackOrigin';

  musicPlayer.on('current-time-changed', currentTime => {
    store.dispatch({ type: 'SET_CURRENT_TIME', origin: playbackOrigin, currentTime });
  });

  musicPlayer.on('playback-finished', () => {
    store.dispatch({ type: 'STOP_PLAYING', origin: playbackOrigin });
  });

jacobp100

const middleware = () => store => {
  const fileWatcher = new FileWatcher();
  fileWatcher.on('file-changed', filename => {
    store.dispatch({ type: 'FILE_CHANGED', filename });
  });

  // Make sure we're watching files that may be included in the store's initial state
  const initialFiles = store.getState().activeFiles;
  fileWatcher.watchFiles(initialFiles);

jacobp100

const fetch = (url, params) => ({
  type: 'FETCH',
  url,
  params,
});

const fetchMiddleware = fetchImplementation => store => next => action => {
  if (action.type === 'FETCH') {
    const { url, params } = action;
    const token = store.getState().token;

jacobp100

import { createStore, applyMiddleware, combineReducers } from 'redux';

const middlewares = applyMiddleware(
  thunk,
  fetchMiddleware(fetch, 'http://api.server.com')
);
const store = createStore(reducers, initialState, middlewares);