middlewario v1.0.1

MiddleWario

A small middleware for Redux. Track side effects, persist unserializable data, do things that don't depend on your react tree. That kind of stuff.

Usage

Build a 'ware that does a thing when you get an action. They can be async if you like. Nobody waits for them. Don't bother returning. Just deal with your side effects, and when they are done, trigger some more actions.

const eatFood = (dispatch) => async (action) => {
  if (action.type === EAT_FOOD_ACTION) {
    await gulp();
    await burp();
    dispatch(foodEatenAction('Mmmm. Delicious.'))
  }
};

Now, add it to your middleware chain with middlewario.

const warioware = middlewario([eatFood]);

const store = createStore(reducer, createMiddleware(warioware))

Bam. Done.

Model side effects as easily as you like.

API

(wareConstructors) => ({ getState, dispatch }) => {
  const wares = wareConstructors
    .map(wereConstructor => wereConstructor(dispatch, getState));

  return (next) => (action) => {
    wares.forEach(ware => ware(action));
    next(action);
  };
};

Whoops that was the entire source. Oh well. It's not that complicated.

Even Leaner!

Use middlewaluigi instead to make an even skinnier action! Only async, and can only return one action.

const eatFood = async (action) => {
  if (action.type === EAT_FOOD_ACTION) {
    await gulp();
    await burp();
    return foodEatenAction('Mmmm. Delicious.');
  }
};

Seriously just look at the source code for a how-to-use.

Advanced

Hydration

This is a neat place to put your hydration logic, especially if it sits inside your app rather than around it.

const hydrator = async (action, getState) => {
  switch (action.type) {
    case 'REQUESTED_HYDRATE':
      try {
        const hydratedState = await getStoredState();
        return { type: 'HYDRATE_SUCCEEDED', hydratedState }
      } catch (error) {
        return { type: 'HYDRATE_FAILED', errorMessage: error.message };
      }
    case 'REQUESTED_FREEZE':
      try {
        const frozenState = getState();
        await setStoredState(frozenState);
        return { type: 'FREEZE_SUCCEEDED' };
      } catch (error) {
        return { type: 'FREEZE_FAILED', errorMessage: error.message };
      }
    default: break;
  }
};

const reducer = (state, action) => {
  switch (action.type) {
    case 'HYDRATE_SUCCESS':
      return action.hydratedState;
  }
};

const App = ({ hydrate, freeze }) => [
  <button onClick={hydrate}>Hydrate State</button>,
  <button onClick={freeze}>Freeze State</button>,
];

const mapDispatchToProps = dispatch => {
  hydrate: () => dispatch({ type: 'REQUESTED_HYDRATE' }),
  freeze: () => dispatch({ type: 'REQUESTED_FREEZE' }),
};

const ConnectedApp = connect(null, mapDispatchToProps)(App);

Cached Services

Wario remembers grudges. And other things that need to be persisted outside of the serializeable state, like caches.

const buildService = () => {
  getAsyncData: (path) => fetch(`example.com/${path}`)
    .then(response => response.json())
    .then(body => body.data),
};

const cachedService = (dispatch) => {
  const { getAsyncData } = buildService();
  const cache = new Map();

  return async (action) => {
    if (action.type === 'SERVICE_REQUESTED') {
      const hasCache = cache.has(action.path);
      const data = hasCache ? cache.get(data) : await getAsyncData(action.path);
      dispatch({ type: 'SERVICE_SUCCESS', data });
    }
  };
};