# Polymer App Toolbox - Starter Kit with custom build

[![Build Status](https://travis-ci.org/PolymerElements/generator-polymer-init-custom-build.svg?branch=master)](https://travis-ci.org/PolymerElements/generator-polymer-init-custom-build)

This template is a starting point for building apps using a drawer-based
layout. The layout is provided by `app-layout` elements.

This template, along with the `polymer-cli` toolchain, also demonstrates use
of the "PRPL pattern" This pattern allows fast first delivery and interaction with
the content at the initial route requested by the user, along with fast subsequent
navigation by pre-caching the remaining components required by the app and
progressively loading them on-demand as the user navigates through the app.

The PRPL pattern, in a nutshell:

* **Push** components required for the initial route
* **Render** initial route ASAP
* **Pre-cache** components for remaining routes
* **Lazy-load** and progressively upgrade next routes on-demand

Also have a custom gulp process leveraging [polymer-build](https://github.com/Polymer/polymer-build),
the library powering [Polymer CLI](https://github.com/Polymer/polymer-cli).

### Setup

##### Prerequisites

First, install [Polymer CLI](https://github.com/Polymer/polymer-cli) and
generator-polymer-init-custom-build using [npm](https://www.npmjs.com) (we
assume you have pre-installed [node.js](https://nodejs.org)).

    npm install -g polymer-cli
    npm install -g generator-polymer-init-custom-build

Second, install [Bower](https://bower.io/) using [npm](https://www.npmjs.com)

    npm install -g bower

##### Initialize project from template

    mkdir my-app
    cd my-app
    polymer init polymer-starter-kit-custom-build

### Start the development server

This command serves the app at `http://127.0.0.1:8081` and provides basic URL
routing for the app:

    polymer serve

### Build

The included `gulpfile.js` relies on [the `polymer-build` library](https://github.com/Polymer/polymer-build),
the same library that powers Polymer CLI. Out of the box it will clean the
`build` directory, and provide image minification. Follow the comments in the
`gulpfile.js` to add additional steps like JS transpilers or CSS preprocessors.

`gulpfile.js` also generates a `service-worker.js` file with code to pre-cache
the dependencies based on the entrypoint and fragments specified in
`polymer.json`.

    npm run build

### Preview the build

This command serves your app.

    polymer serve build/

### Run tests

This command will run [Web Component Tester](https://github.com/Polymer/web-component-tester)
against the browsers currently installed on your machine:

    polymer test

If running Windows you will need to set the following environment variables:

- LAUNCHPAD_BROWSERS
- LAUNCHPAD_CHROME

Read More here [daffl/launchpad](https://github.com/daffl/launchpad#environment-variables-impacting-local-browsers-detection)

### Adding a new build step

The `gulpfile.js` already contains an example build step that demonstrates how
to run image minification across your source files. For more examples, refer to
the section in [the polymer-build README on extracting inline sources](https://github.com/Polymer/polymer-build#extracting-inlined-cssjs).

### Adding a new view

You can extend the app by adding more views that will be demand-loaded
e.g. based on the route, or to progressively render non-critical sections of the
application. Each new demand-loaded fragment should be added to the list of
`fragments` in the included `polymer.json` file. This will ensure those
components and their dependencies are added to the list of pre-cached components
and will be included in the build.