Polymer Hacker News clone
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Latest commit 82d8861 Jun 27, 2018


Polymer Hacker News client

Very basic Hacker News Progressive Web App client made with Polymer 2.

Demo Screenshot
Try the Demo!


  • Lighthouse 92/100
  • Interactive (Emerging Markets) 2.7s
  • Interactive (Faster 3G) 2.0s


Progressive Web App

  • Uses Service Worker to cache data and work offline
  • App Manifest for installing to homescreen

Polymer CLI

hn-polymer-2 was created by using the Polymer CLI, a collection of tools to make building Web Components and Polymer apps easier.

Using Polymer Starter Kit template provided by the CLI made following the PRPL pattern easy from the start.

PRPL pattern

The PRPL pattern, in a nutshell:

  • Push components required for the initial route using http2 and Server Push
  • Render initial route ASAP
  • Pre-cache components for remaining routes using Service Worker
  • Lazy-load and progressively upgrade next routes on-demand


Firebase provides easy http2-enabled static hosting, a real-time database, server functions, and edge-caching all over the globe.


  1. Install polymer-cli globally

    npm install -g polymer-cli
  2. Install the dependencies

    npm install
  3. Serve the development version

    polymer serve
  4. (Optional) Enable firebase function based HN API proxy

    • Edit sw-precache-config.js
    • Edit src/hn-app.html
  5. Build

    polymer build
  6. Test deployment

    polymer serve build/es5-bundled
  7. Deploy after setting up a firebase project

    firebase deploy


  • use firebase functions to differentially serve for polyfills
  • use firebase functions to push route data for all pages, not just main routes
  • use official HackerNews Firebase API to support realtime updates
  • Automate using firebase function API proxy when deploying