Polymer Starter Kit
A starting point for building web applications with Polymer 1.0
Included out of the box:
- Polymer, Paper and Iron elements
- Material Design layout
- Routing with Page.js
- Unit testing with Web Component Tester
- Offline-first setup through Platinum Service Worker elements
- End-to-end Build Tooling (including Vulcanize)
To take advantage of Polymer Starter Kit you need to:
- Get a copy of the code.
- Install the dependencies if you don't already have them.
- Modify the application to your liking.
- Deploy your production code.
Get the code
Download and extract Polymer Starter Kit to where you want to work.
The standard version of Polymer Starter Kit comes with tools that are very handy when developing a Polymer app. If you'd like to get started without installing any new tools, see Polymer Starter Kit Light in the Releases page.
Quick-start (for experienced users)
With Node.js installed, run the following one liner from the root of your Polymer Starter Kit download:
npm install -g gulp bower && npm install && bower install
Prerequisites (for everyone)
The full starter kit requires the following major dependencies:
- npm, the node package manager, installed with Node.js and used to install Node.js packages.
- gulp, a Node.js-based build tool.
- bower, a Node.js-based package manager used to install front-end packages (like Polymer).
To install dependencies:
- Check your Node.js version.
The version should be at or above 0.12.x.
If you don't have Node.js installed, or you have a lower version, go to nodejs.org and click on the big green Install button.
npm install -g gulp bower
This lets you run
bower from the command line.
- Install the starter kit's local
cd polymer-starter-kit && npm install && bower install
This installs the element sets (Paper, Iron, Platinum) and tools the starter kit requires to build and serve apps.
Serve / watch
This outputs an IP address you can use to locally test and another that can be used on devices connected to your network.
This runs the unit tests defined in the
app/test directory through web-component-tester.
Build & Vulcanize
Build and optimize the current project, ready for deployment. This includes linting as well as vulcanization, image, script, stylesheet and HTML optimization and minification.
Polymer 1.0 introduces a shim for CSS custom properties. We take advantage of this in
app/styles/app-theme.html to provide theming for your application. You can also find our presets for Material Design breakpoints in this file.
Read more about CSS custom properties.
Web apps built with Polymer Starter Kit come configured with support for Web Component Tester - Polymer's preferred tool for authoring and running unit tests. This makes testing your element based applications a pleasant experience.
Read more about using Web Component tester.
Polymer uses Bower for package management. This makes it easy to keep your elements up to date and versioned. For tooling, we use npm to manage Node.js-based dependencies.
Polymer Starter Kit offers an offline-first experience thanks to Service Worker and the Platinum Service Worker elements. New to Service Worker? Read the following introduction to understand how it works.
Our default offline setup should work well for relatively simple applications. For more complex apps, we recommend learning how Service Worker works so that you can make the most of the Platinum Service Worker element abstractions.
Filing bugs in the right place
If you experience an issue with Service Worker support in your application, check the origin of the issue and use the appropriate issue tracker:
- For all other issues, feel free to file them here.
I get an error message about "Only secure origins are allowed"
Service Workers are only available to "secure origins" (HTTPS sites, basically) in line with a policy to prefer secure origins for powerful new features. However http://localhost is also considered a secure origin, so if you can, developing on localhost is an easy way to avoid this error. For production, your site will need to support HTTPS.
How do I debug Service Worker?
If you need to debug the event listener wire-up use
What are those buttons on chrome://serviceworker-internals?
This page shows your registered workers and provides some basic operations.
- Unregister: Unregisters the worker.
- Start: Starts the worker. This would happen automatically when you navigate to a page in the worker's scope.
- Stop: Stops the worker.
- Sync: Dispatches a 'sync' event to the worker. If you don't handle this event, nothing will happen.
- Push: Dispatches a 'push' event to the worker. If you don't handle this event, nothing will happen.
- Inspect: Opens the worker in the Inspector.
In order to guarantee that the latest version of your Service Worker script is being used, follow these instructions:
- After you made changes to your service worker script, close all but one of the tabs pointing to your web application
- Hit shift-reload to bypass the service worker as to ensure that the remaining tab isn't under the control of a service worker
- Hit reload to let the newer version of the Service Worker control the page.
If you find anything to still be stale, you can also try navigating to
chrome:serviceworker-internals (in Chrome), finding the relevant Service Worker entry for your application and clicking 'Unregister' before refreshing your app. This will (of course) only clear it from the local development machine. If you have already deployed to production then further work will be necessary to remove it from your user's machines.
Not yet ready for Service Worker support?
If for any reason you decide that Service Worker support isn't for you, you can disable it from your Polymer Starter Kit project using these 3 steps:
- Remove 'precache' from the list in the 'default' gulp task (gulpfile.js)
- Remove the two Platinum Service Worker elements (platinum-sw/..) in app/elements/elements.html
- Remove references to the platinum-sw elements from your application index.
You will also want to navigate to
chrome://serviceworker-internals and unregister any Service Workers registered by Polymer Starter Kit for your app just in case there's a copy of it cached.
generator-polymer now includes support for Polymer Starter Kit out of the box.
Frequently Asked Questions
Where do I customise my application theme?
Theming can be achieved using CSS Custom properties via app/styles/app-theme.html.
You can also use
app/styles/main.css for pure CSS stylesheets (e.g for global styles), however note that Custom properties will not work there under the shim.
A Polycast is also available that walks through theming using Polymer 1.0.
Where do I configure routes in my application?
Why are we using Page.js rather than a declarative router like
<more-routing> (in our opinion) is good, but lacks imperative hooks for getting full control
over the routing in your application. This is one place where a pure JS router shines. We may
at some point switch back to a declarative router when our hook requirements are tackled. That
said, it should be trivial to switch to
<more-routing> or another declarative router in your
own local setup.
Where can I find the application layouts from your Google I/O 2015 talk?
App layouts live in a separate repository called app-layout-templates. You can select a template and copy over the relevant parts you would like to reuse to Polymer Starter Kit.
You will probably need to change paths to where your Iron and Paper dependencies can be found to get everything working.
This can be done by adding them to the
Something has failed during installation. How do I fix this?
Our most commonly reported issue is around system permissions for installing Node.js dependencies.
We recommend following the fixing npm permissions
guide to address any messages around administrator permissions being required. If you use
to work around these issues, this guide may also be useful for avoiding that.
If you run into an exception that mentions five optional dependencies failing (or an
EEXIST error), you
may have run into an npm bug. We recommend updating to npm 2.11.0+
to work around this. You can do this by opening a Command Prompt/terminal and running
npm install firstname.lastname@example.org -g. If you are on Windows,
Node.js (and npm) may have been installed into
C:\Program Files\. Updating npm by running
npm install email@example.com -g will install npm
%AppData%\npm, but your system will still use the npm version. You can avoid this by deleting your older npm from
as described here.
If the issue is to do with a failure somewhere else, you might find that due to a network issue
a dependency failed to correctly install. We recommend running
npm cache clean and deleting the
node_modules directory followed by
npm install to see if this corrects the problem. If not, please check the issue tracker in case
there is a workaround or fix already posted.
I'm having trouble getting Vulcanize to fully build my project on Windows. Help?
Some Windows users have run into trouble with the
elements.vulcanized.html file in their
not being correctly vulcanized. This can happen if your project is in a folder with a name containing a
space. You can work around this issue by ensuring your path doesn't contain one.
There is also an in-flight issue
where some are finding they need to disable the
inlineCss option in our configuration for Vulcanize
to correctly build. We are still investigating this, however for the time-being use the workaround if
you find your builds getting stuck here.
At the bottom of
app/index.html, you will find a build block that can be used to include additional
scripts for your app. Build blocks are just normal script tags that are wrapped in a HTML
comment that indicates where to concatenate and minify their final contents to.
Below, we've added in
script3.js to this block. The line
<!-- build:js scripts/app.js --> specifies that these scripts will be squashed into
during a build.
<!-- build:js scripts/app.js --> <script src="scripts/app.js"></script> <script src="scripts/script2.js"></script> <script src="scripts/script3.js"></script> <!-- endbuild-->
I'm finding the installation/tooling here overwhelming. What should I do?
Don't worry! We've got your covered. Polymer Starter Kit tries to offer everything you need to build and optimize your apps for production, which is why we include the tooling we do. We realise however that our tooling setup may not be for everyone.
If you find that you just want the simplest setup possible, we recommend using Polymer Starter Kit light, which is available from the Releases page. This takes next to no time to setup.
Polymer Starter Kit is a new project and is an ongoing effort by the Web Component community. We welcome your bug reports, PRs for improvements, docs and anything you think would improve the experience for other Polymer developers.