Yeoman generator for Polymer projects

Introduction

Polymer is a library of polyfills and sugar which enable the use of Web Components in modern browsers. The project allows developers to build apps using the platform of tomorrow and inform the W3C of places where in-flight specifications can be further improved.

generator-polymer provides Polymer scaffolding using Yeoman (a scaffolding tool for the web), letting you easily create and customize Polymer (custom) elements via the command-line and import them using HTML Imports. This saves you time writing boilerplate code so you can start writing up the logic to your components straight away.

Features

• A Polymer app scaffold built with HTML5 Boilerplate
• Sub-generator to create Polymer elements for your app
• Boilerplate to create reusable Polymer elements
• Quick deploy to GitHub pages
• All the goodness of seed-element (docs & landing page for your element)
• Support for SASS/SCSS and Autoprefixer
• PageSpeed Insights for performance tuning
• web-component-tester support

Installation

Install the generator npm install -g generator-polymerelement

Make a new directory and cd into it mkdir -p my-project && cd $_

Scaffold a new Polymer project: yo polymer "name-project"

Generators

Available generators:

• polymer (aka polymer:app)
• polymer:seed

Note: Generators are to be run from the root of your app

App

Sets up a new Polymer app, generating all the boilerplate you need to get started.

Example:

yo polymer project-Name

Options

--docs, include core-component-pages docs with your element and demo.html
--path, override default directory structure, ex: --path foo/bar will put your element in app/elements/foo/bar

Seed

Generates a reusable polymer element based on the seed-element workflow. This should only be used if you're creating a standalone element repo that you intend to share with others via bower. If you're just building a Polymer app, stick to the Element generator.

The seed-element generator will construct a new element and its directory for you. Be aware: all bower dependencies will be installed as siblings of the newly generated element. Make sure that you generate the seed element within a directory that is intended to contain multiple components!

Example:

mkdir -p components && cd $_
yo polymer:seed x-foo

Testing

The project generated by yo polymer contains support for web-component-tester. The following commands are included:

Run local tests (in terminal):

grunt|gulp test:local

Run remote tests with SauceLabs:

grunt|gulp test:remote

See the web-component-tester readme for configuration options.

Gotchas

The elements.html file

The app generator will produce an elements.html file where you can place your imports. This file will be vulcanized when you run the default grunt or gulp tasks. You'll want to make sure that elements.html is the only import in your index.html file, otherwise there's a good chance you'll accidentally load Polymer twice and break the app.

Autoprefixer and style elements

The Autoprefixer task will not work with style elements mixed into HTML files (it breaks). Meaning, if you drop a style tag inside of your Polymer element, it will not be processed by Autoprefixer. Only external CSS files can/will be processed by Autoprefixer.

Contribute

See the contributing docs

When submitting an issue, please follow the guidelines. Especially important is to make sure Yeoman is up-to-date, and providing the command or commands that cause the issue.

License

BSD license