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    A generator for creating sophisticated enterprise level universal React SPAs. Have server side rendering, lightening fast pages, SEO support and much much more...

    Are you exhausted by the exercise of stitching together all the essential pieces to constitute a comprehensive SPA? Are you frustrated by getting painted into corners with bloated frameworks and mired in their black boxes? Whether you're looking to create a SPA application, jump-start your own enterprise framework, or simply want to see and learn how all the magic works, you're in the right place.

    Paragons brings together some of the top tooling, modules, and approaches of modern SPA development and combines them into a simple elegant box.

    Dislike a particular aspect or need to tack in something else? Begin by reading the Walkthrough below and then dig in. You will find valuable documentation on all major components.


    For further information and discussion see corresponding sections below.


    In development mode modifications are automatically detected and made available via HMR without restart. Neither the server bundle nor the client chunks are not emitted. Source maps are inlined.

    npx -p yo -p generator-paragons generator-paragons my-app
    cd spa-my-app
    npm start

    Then open http://localhost:3000

    Note: npx is available on npm 5.2+ and higher. If you are on a previous version see Alternative Installations below.


    In production mode the server bundle and the client chunks are emitted to the dist directory. In addition the client chunks are optimized(minification, tree shook, etc.). Source maps are emitted per chunk.

    npm run build
    npm run start-prod

    Webpack v4 with Hot Module Replacement (HMR)

    • Single simple webpack.config.js which handles both the client and the server side.

    Server Side Rendering (SSR)

    Pages are built on the server side and can be immediately rendered in the clients browser. Not only can this be a huge performance gain but, it is absolutely essential for SEO.

    Pre-render Task Support

    There can be a number of operations which need to be performed prior to inducing the SSR. One of the main challenges is pre-loading data in to the Redux store before the SSR cycle is invoked. That can be easily accomplished by registering a preloadData thunk function whic returns a Promise on your component. server.js will automatically pick up all preloadData promises and add them to the pre-render tasks. This capability is demonstrated by PreloadDataPage.js

    Code Splitting

    Code splitting allows you to beak up your application into chunks. In practice this is usually done per route so each page is served with only what it needs to render. Thanks to dynamic imports and React Loadable this becomes a simple game. This capability is demonstrated by CodeSplitPage.js.

    Key Concept

    Webpack is a static module bundler. That is given an entry point it will walk the imports and requires bundling everything in to JS file. The key is to break that static path by using Dynamic imports. Simply use Webpacks import() function as opposed to the import statement.

    Styling (CSS, Sass)

    Out of the box CSS and Sass support with autoprefixing.

    Testing and Code Coverage (Jest and Enzyme)

    Tests are located in the tests directory. As a matter of practice it is recommended to mirror the src directory structure.

    React components can be tested with Enzyme

    Note: The test env of the root .babelrc ensures the code is transpiled.

    Internationalization (i18n)

    Components can use the React Intl API right out of the box. All translations are maintained under `src/i18n/. This capability is demonstrated by i18nPage.js.

    The users locale is determined via the Express middleware express-locale in server.js and both stored into the Redux store and feed to <IntlProvider> in HostPage.js.

    The translations are loaded by Webpacks import() function which is very cool because they are automatically encapsulated in a chunk and can be dynamically loaded. Plus they will be cached via the standard browser caching and only downloaded initially or if they are updated!

    SEO Support

    This SEO game is really only applicable to publicly available pages which can be sever side rendered. That is because the crawlers walk the site by following all the available links. As they request them, the titles, meta tags, keywords, etc. need to be appropriately set for the page / route.

    These capabilities are embedded into PurePage.js which component pages can extend.

    PageSupport.js is a singleton per request/response cycle which centralizes critical page data points including the title and meta tags.

    Note: Although it is possible to update the the DOM on the client side; that is update the title, meta tags, keywords, etc. once the SPA is in effect, it's useless as the crawlers as they can't navigate the SPA. That being said the title is a special case as it is reflected in the browser and impacts the users experience. Therefore PageSupport.js does update it in real time.

    Secure Routes

    For some routes/pages the user needs to be authenticated. This can be accomplished by setting secure="true" on the route. See the /profile route for example usage. When the user attempts to access a secure route, they are redirected to the login page for authentication. After successful authentication, the user is then redirected to the route they were initially trying to access...

    _Note: The actual authentication implementation in LoginPage.js.handleLogin is stubbed for example purposes and will accept any password except "fail" which can be used to test drive a failed login scenario. That being said it does give you a solid starting point to work with including preparation of password hash, seeding profile information in the Redux store, a logout route, and a profile page.

    Deferred Rendering (aka Above the Fold Rendering)

    This is a technique for increasing the page render time. The idea is that you only take the cost of rendering the content which the user will see or what is considered to be above the fold.

    This capability is demonstrated by DeferRenderPage.js which leverages the DeferRender.js component.

    Note(1): In practice the cost is usually the the supporting service operations not the actual render.

    Note(2): If you are truly concerned with the visible portion, see react-loadable-visibility.


    An inbound request is first handled by Express in server.js which does some up front work like determining the users locale, setting the root directory from which to serve static assets, and configures middleware. If the mode is development then hot reloading is also setup.

    Next serverRenderer.js checks to see if the requested path matches a configured route. If so it determine users locale and language, creates the Redux store, loads the international locale data and the translations, and performs all pre-render tasks like data loading. Finally it delegates to HostPage.js which performs the actual server side render and assembles the initial HTML is sent to and rendered immediately in the clients browser. In the background, the SPA is hydrated into a fully functional client side application by client.js.From there the SPA is in full effect.

    Alternative Installations

    Local Installation (preferred)

    Here you install yo and generator-paragons locally and then invoke generator-paragons. This approach is generally more acceptable because each time you do it your ensured to be working with the latest and greatest Paragons generator because you are starting fresh each time (npx is much fancier).

    mkdir spa-my-app
    cd spa-my-app
    npm i yo generator-paragons
    ./node_modules/.bin/yo paragons

    Global Installation (use npx or local install; this is just here for educational purposes)

    Here generator-paragons is installed globally but, that is not optimal because you could be out of sync with the latest and greatest.

    npm i -g yo yeoman-generator generator-paragons
    mkdir my-app
    cd my-app
    yo paragons my-app


    Copyright (c) 2018-present, Joseki Technologies Inc.

    Licensed under the Apache License, Version 2.0.


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