create-evergreen-app

Overview

A starter project for getting up and running with an evergreen web application development stack designed by, and for, today's modern web.

Project Goals

The goal of Project Evergreen is to march alongside the web and demonstrate those features projects like these, that can be a reference and starting point, so that both developers and users can benefit from a modern application intended for modern browsers. Evergreen Web Applications aim to be performant, promote usage of modern web features, be accessible to a wide range of users, and be a productive experience for developers.

Getting Started

Make sure you have a LTS version of Node.js (>= 10.x) and then follow these steps to get up and running:

# 1) Create new evergreen app
$ npx create-evergreen-app my-app

# 2) Change Directory
$ cd my-app

# 3) Start developing!
$ npm start

# or

$ yarn start

You can also run the installer locally by cloning the repo and using NodeJS

$ git clone https://github.com/ProjectEvergreen/create-evergreen-app.git
$ cd create-evergreen-app
$ npm ci # install project dependencies
$ node ./tasks/cea-install.js my-app # you can pass other supported CLI params here as well

You can now copy the my-app/ folder anywhere you want and start developing!

Additional CLI Commands

Here are some additional commands you can run while running npx create-evergreen-app

# install dependencies with Yarn instead of npm
$ npx create-evergreen-app my-app --yarn

# get help
$ npx create-evergreen-app --help

# get the version
$ npx create-evergreen-app --version

Developing with CEA

To start developing, simply open the my-app folder in your favorite IDE (VSCode has great modern JavaScript support) and start editing and adding files as you need in src/.

Development Workflows

Automated tasks have been made available as npm scripts that you can run from the command line using yarn or npm run:

• develop - To start a development server with live reload and file watching
• build - Generate a production build of the app for deployment
• serve - Locally serve a production build
• test - Run unit tests in TDD mode (prepend with NODE_ENV=production for "single run" usage)
• start - alias to the develop task

e.g. to start developing, run

# yarn
$ yarn develop

or

# npm
$ npm run develop

Package Management

Your team may choose to use either npm or Yarn, just make sure to pick one and remove the other manager's lock file. Make sure to update the lock file whenever adding / removing a package.

Guides

These are some guides related to configuring different parts of this application to customize it for your needs.

Folder Structure

There is no right or wrong folder structure per se as with most decisions relating to technology, it's about finding the best tool for the job. Pick the conventions that fit your team / project best.

That said, CEA does come with with a lightly opinionated structure in the src/ directory as one of the main goals of a good folder structure should be to assist in the finding of files / code faster and being predicatable. Here is some info on the approach presented / suggested in this repo:

• index.js - Main Entry point into the application (defined in webpack.config.common.js)
• index.html - Defines the HTML "shell" of the application.
• app/ - The top level "app" component, that will be used to bootstrap the application.
• components/ - Essentially all the custom elements for an app will go here, encapsulating all reusable UI logic.
• pages/ - Routable states and / or views that users will navigate to within an application.
• services/ - Utilities for making (RESTful) API calls, convenience "wrappers" around browser APIs (Web Storage), etc. These generally don't interact with the DOM (that's what components are for).

Unit tests are recommended to be kept side by side with the component / class / etc. For integration and E2E tests, consider making a test/ directory alongside the src/ directory and put those tests there.

Setting Up (API) Proxies

In webpack.config.develop.js and lws.config.js are sections for setting up proxies for routing requests, say to an API running in your development envrionment. Edit the placeholders to match your particular needs.

CSS + Shadow DOM

// TODO

Performance

Performance is an important consideration for developing and maintaing any modern web application. Out of the box, this project uses webpack's default settings for performance budgets and will error when its thresholds are exceeded.

The goal of this project will be to support good code splitting and lazy loading strategies by default to allow apps to scale horizontally as more pages / features / dependencies get added.

To learn more about performance best practices for modern web application development, check out the wiki.

Unit Testing

For convenience, Create Evergreen App comes with the dependencies needed to run two browsers out of the box

1. Chrome (headless w/Puppeteer)
2. Firefox

Using Firefox

1. Firefox (and other browsers) will likely need Custom Elements and Shadow DOM polyfilled. To add this polyfill in Karma, uncomment the lines in the files array in karma.conf.js related to ~@webcomponents.
2. Add Firefox to the browsers array in karma.conf.js.

• For information on adding more browsers, see the Karma docs.
• For more information on testing in general, see our wiki!.

Chrome headless is enabled by default since it is the most portable between local and continuous integration environments.

Acknowledgements

This project is made by possible with the much appreciated existence of tools like:

• webpack
• LitElement
• Babel
• PostCSS
• Browserslist
• WebComponents.org

And of course, nods and kudos go out to the maintainers of Create React App (CRA) and Pascal Shlip (@thepassle) of Create Lit App for the inspiration.

Thank you, to all of you!