mern-starter

MERN is a scaffolding tool which makes it easy to build isomorphic apps using Mongo, Express, React and NodeJS. It minimizes the setup time and gets you up to speed using proven technologies.

Quickstart

  npm install -g mern-cli
  mern your_new_app
  cd your_new_app
  npm install
  npm start

Note : Please make sure your MongoDB is running. For MongoDB installation guide see this.

File Structure

Webpack Configs

MERN uses Webpack for bundling modules. There are two types of Webpack configs provided webpack.config.dev.js (for development) and webpack.config.prod.js (for production).

The Webpack configuration is minimal and beginner-friendly. You can customize and add more features to it for production build.

Server

MERN uses express web framework. Our app sits in server.js where we check for NODE_ENV.

If NODE_ENV is development we apply Webpack middlewares for bundling and Hot Module Replacement.

Server Side Rendering

We use React Router's match function for handling all page requests so that browser history works.

All the routes are defined in shared/routes.js. React Router renders components according to route requested.

// Server Side Rendering based on routes matched by React-router.
app.use((req, res) => {
    match({
        routes,
        location: req.url
    }, (err, redirectLocation, renderProps) => {
        if (err) {
            return res.status(500).end('Internal server error');
        }

        if (!renderProps) {
            return res.status(404).end('Not found!');
        }

        const initialState = {
            posts: [],
            post: {}
        };

        const store = configureStore(initialState);

        fetchComponentData(store.dispatch, renderProps.components, renderProps.params).then(() => {
            const initialView = renderToString(
                <Provider store = {store} >
                  <RouterContext {...renderProps}/>
                </Provider>
            );

            const finalState = store.getState();

            res.status(200).end(renderFullPage(initialView, finalState));
        }).catch(() => {
            res.end(renderFullPage('Error', {}));
        });
    });
});

match takes two parameters, first is an object that contains routes, location and history and second is a callback function which is called when routes have been matched to a location.

If there's an error in matching we return 500 status code, if no matches are found we return 404 status code. If a match is found then we need to create a new Redux Store instance.

Note: A new Redux Store is populated afresh on every request.

fetchComponentData is the key function. It takes three params : first is a dispatch function of Redux store, second is an array of components that should be rendered in current route and third is the route params. fetchComponentData collects all the needs (need is an array of actions that are required to be dispatched before rendering the component) of components in the current route. It returns a promise when all the required actions are dispatched. We render the page and send data to client for client-side rendering in window.__INITIAL_STATE__.

Shared

Shared directory contains all the components, routes, actions and reducers.

Client

Index.js simply does client side rendering using the data provided from window.__INITIAL_STATE__.

Roadmap

####MERN Starter

Add GraphQL to mern-starter
Add SCSS support
Improve file structure (needs discussion)

####MERN CLI

Generators for Containers, Components, Routes, Reducers, Actions
Generators for Models, Router, Controllers
Add flags to CLI e.g. for adding lifecycle

License

MERN is released under the MIT License.

nemisj/mern-starter