Contributing #

First off, thanks for considering making a contribution to Liquid Oxygen! 👍

The following is a set of guidelines for contributing to Liquid Oxygen. These are not rules. So use your best judgment, and feel free to propose changes to this document in a pull request.

Code of conduct #

This project and everyone who participates in it is governed by our Code of Conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to liquid@emdgroup.com.

Reporting bugs #

This section guides you through submitting a bug report for Liquid. Following these guidelines helps maintainers and the community understand your report ✏️, reproduce the behavior 💻💻, and find related reports 🔎.

Before creating bug reports, please check this list as you might find out that you do not need to create one. Fill out our bug report template and include as many details as possible. The more information we have, the more likely we will be able to resolve the issue in a short time.

Before submitting a bug report #

• Most importantly, check if you can reproduce the problem in the latest version of Liquid.
• Perform a search in existing issues to see if the problem has already been reported. If it has and the issue is still open, upvote the issue report or add a comment to the existing issue, if you think it contains relevant information which will help resolve it, instead of opening a new one.

How do I submit a (good) bug report? #

Bugs are tracked as GitHub issues. Create an issue and provide the following information by filling in the template.

Explain the problem and include additional details to help maintainers reproduce the problem:

• Use a clear and descriptive title for the issue to identify the problem.
• Describe the exact steps which reproduce the problem in as many details as possible. When listing steps, don't just say what you did, but explain how you did it.
• Provide specific examples to demonstrate the steps. Include links to files or GitHub projects, or copy/pasteable snippets, which you use in those examples. If you're providing snippets in the issue, use Markdown code blocks.
• Describe the behavior you observed after following the steps and point out what exactly is the problem with that behavior.
• Explain which behavior you expected to see instead and why.
• Include screenshots and animated GIFs which show you following the described steps and clearly demonstrate the problem. If you use the keyboard while following the steps, record the GIF with the Keybinding Resolver shown. You can use this tool to record GIFs on macOS and Windows, and this tool or this tool on Linux.
• If the problem wasn't triggered by a specific action, describe what you were doing before the problem happened and share more information using the guidelines below.

Provide more context by answering these questions:

• Did the problem start happening recently (e.g. after updating to a new version of Liquid)?
• If the problem started happening recently, can you reproduce the problem in an older version of Liquid? What's the most recent version in which the problem doesn't happen?
• Can you reliably reproduce the issue? If not, provide details about how often the problem happens and under which conditions it normally happens.

Include details about your configuration and environment:

• Which version of Liquid are you using? You can get the exact version by running npm list @emdgroup-liquid/liquid inside the working directory of your project.
• Which browser are you using?
• Which browser extensions are installed? Can you reproduce the issue in incognito mode?
• What's the name and version of the OS you're using?
• Which other framework/libraries are you using that may be involved in the issue? Please check https://stenciljs.com/docs/overview for possible known quirks.

Requesting new features #

This section guides you through submitting a feature request for Liquid, including completely new components, new features to existing components and minor improvements to existing functionality. Following these guidelines helps maintainers and the community understand your request ✏️ and find related requests 🔎.

Before submitting a feature request #

• Most importantly, check if you are using the latest version of Liquid.
• Perform a search in the feature backlog to see if a similar feature has already been requested. If it has and the issue is still open or if it has the needed: votes label, upvote the requested feature or add a comment, if you think it contains relevant information that will help drive it forward, instead of opening a new one. If you prefer to discuss with others first, you can start a discussion on GitHub discussions or in our Teams channel.

How do I vote on an existing feature request? #

You can upvote a feature request, if it has the needed: votes label, with a 👍 reaction on the top comment of the issue. The more votes, the higher we prioritize the request.

How do I submit a (good) feature request? #

Feature requests are tracked as GitHub issues. Use our feature request template to create a feature request and include as many details as possible:

• Use a clear and descriptive title for the issue to identify the suggestion.
• Provide a detailed description of the requested feature.
• Provide specific examples to demonstrate how the feature works. Include copy/pasteable snippets which you use in those examples, as Markdown code blocks.
• List some other UI libraries or applications where this feature already exists.
• Include screenshots and animated GIFs of similar features implemented in other UI libraries or applications, to help demonstrate what you expect from the feature. You can use this tool to record GIFs on macOS and Windows, and this tool or this tool on Linux.
• Explain why this feature would be useful to most Liquid Oxygen users and why it is not something that can or should be implemented as a separate community package.
• Specify which version of Liquid you are using. You can get the exact version by running npm list @emdgroup-liquid/liquid inside the working directory of your project.
• Specify the name and version of the browser you are using.
• Specify the name and version of the OS you are using.

Contributing code #

Unsure where to begin contributing to Liquid Oxygen? You can start by looking through beginner and help wanted issues:

• Beginner issues - issues which should only require a few lines of code, and a test or two.
• Help wanted issues - issues which should be a bit more involved than beginner issues.

Both issue lists are sorted by total number of comments. While not perfect, the number of comments is a reasonable indicator for the impact your contribution can have.

Local development #

Before you can contribute any code, you will most likely want to setup a local development environment. Follow these steps to get started:

1. Install Git, Node.js and Yarn.

2. Clone the project (or your fork of it):

git clone git@github.com:emdgroup-liquid/liquid.git

3. Install dependencies inside the project folder:

corepack enable && yarn

4. Trigger the generation of type definitions within the src/liquid folder by running the project build task (this step is only required before starting the local dev server for the first time):

yarn build

5. Start up the local development server:

yarn start

6. Now head over to http://localhost:8080 - you shoud see the Liquid docs site.

Project structure #

This project consists of different parts and pieces, each with its own purpose. Familiarize yourself with these parts and pieces, so that you find your way quicker to the relevant spot where you would like to contribute.

├── README.md
├── CODE_OF_CONDUCT.md
├── CONTRIBUTING.md
├── SECURITY.md
├── LICENSE.md
├── package.json                  # Please have a look at the scripts section inside the
│                                 # package.json file.
│                                 # You can also run `npm run` to get a list of all
│                                 # available commands.
├── .devcontainer
│   └── devcontainer.json         # GitHub codespaces dev container configuration.
├── .github
│   └── workflows/ci-cd.yml       # CI/CD pipeline config file.
├── .vscode
│   └── task.json                 # Task configurations for Visual Studio Code.
├── .env                          # The .env file is not under version control.
│                                 # It contains sensitive data, such as credentials
│                                 # used to authenticate oneself against
│                                 # an API. We currenly do this for fetching design
│                                 # tokens from Figma.
├── bin                           # Contains scripts to be included in the bundle
│                                 # for execution with npx.
├── config                        # Folder containing all sorts of configuration files.
│   ├── .eleventy.cjs             # The Liquid Oxygen docs site is powered by 11ty.
│   │                             # See https://www.11ty.dev/
│   ├── .eslintrc.cjs             # eslint is used for linting ts and tsx files.
│   │                             # Please make sure to enable eslint in your code editor.
│   ├── .prettierrc.json          # prettier ensures a consistent code style. Please make
│   │                             # sure to enable prettier in your code editor of choice.
│   ├── .releaserc.cjs            # Config file for semantic-release. See
│   │                             # https://semantic-release.gitbook.io/semantic-release/
│   ├── commitlint.config.cjs     # We use conventional commits and semantic release.
│   ├── postcss.config.docs.cjs   # PostCSS config file for the docs site CSS processing.
│   ├── postcss.config.cjs        # PostCSS config file for Liquid CSS processing.
│   ├── stencil.config.docs.ts    # Stencil config file for the docs site.
│   ├── stylelint.config.cjs      # Stylelint config file. See section about linting
│   │                             # further below.
│   ├── tsconfig.docs.json        # Typescript config file for components used for the
│   │                             # docs site.
│   ├── tsconfig.react.json       # Typescript config file for react component bindings.
│   └── tsconfig.vue.json         # Typescript config file for vue component bindings.
├── .npmignore                    # The .npmignore file is used to keep the package size
│                                 # to a minimum.
│                                 # More about this below.
├── dist                          # Here is the main juice which gets published to npm.
├── dist_docs                     # This folder is served during development. It contains
│                                 # the docs site as well as the necessary liquid files.
├── screenshot                    # This directory contains files related to visual
│                                 # regression testing with Stencil. See
│                                 # https://stenciljs.com/docs/screenshot-visual-diff
├── scripts                       # Contains bash or node script files executed via
│                                 # npm script commands.
├── src                           # The source folder.
│   ├── _data                     # This folder contains data files.
│   │   │                         # See https://www.11ty.dev/docs/data-global/
│   │   └── env.cjs               # Environment variables injected during generation of
│   │                             # the docs site.
│   ├── docs                      # Everything inside this folder is for developing the
│   │   │                         # docs site.
│   │   ├── assets                # Static assets for the docs page reside here.
│   │   ├── components            # Docs components live here.
│   │   ├── global                # Docs global styles live here.
│   │   ├── includes
│   │   │   ├── layout.njk        # The docs site is powered by 11ty. This is the default
│   │   │   │                     # 11ty layout file for the docs site.
│   │   │   │                     # See https://www.11ty.dev/docs/layouts/
│   │   │   └── redirect.njk      # This layout file handles redirects on pages behind
│   │   │   │                     # authentication.
│   │   ├── layouts               # There is one layout component which lives inside this
│   │   │                         # folder.
│   │   ├── pages                 # This folder contains markdown files for general
│   │   │                         # documentation pages, legal stuff and the 404 page.
│   │   └── utils                 # Contains docs utililty files.
│   └── liquid                    # Liquid Oxygen source code lives here.
│       ├── components            # This folder contains all Liquid components including
│       │                         # tests and docs.
│       ├── global                # Here we have global styles. Mainly CSS custom
│       │                         # properties, such as variables for colors, theming,
│       │                         # typography, spacings, shadows etc.
│       │                         # Note that most of these files are auto-generated
│       │                         # using design tokens.
│       └── utils                 # Contains utilities shared between components.
├── stencil.config.ts             # Stencil config file for Liquid components.
├── tsconfig.json                 # Typescript config file for Liquid components.
├── yarn.lock                     # Oh, yes, we use yarn.
└── .yarnrc.yml                   # The yarn configuration file
                                  # (only necessary in CI environment).

As you can see, Liquid Oxygen currenly has a straight forward project structure: One repo, one package.json, no workspaces, just two main directories inside the src/ folder, src/docs/ for the docs site and src/liquid/ for the component library.

Conventions #

Code style #

You probably noticed by now that we use eslint, prettier and stylelint in this project to enforce some code style conventions. Please make sure to enable these tools in your code editor of choice.

Some things are not linted but are still important:

• We prefix Liquid components with ld- and docs components with docs-.
• We use BEM as a methodology for organizing CSS rules.
• We use relative length units in CSS, mostly rem; absolute length units should be avoided (borders and outlines may count as an exception to the rule).
• We use Shadow DOM wherever possible, especially in components which use slots: not using Shadow DOM in such components resutls in a worse performance (due to Stencil's custom slot implementation performing expensive DOM operations) and quirks in React apps. We allow for custom styling of Web Component by applying part attributes to component internal elements and using component specific CSS custom properties where applicable.
• When ever possible, try to provide CSS Components alongside WebComponents using the same CSS file; prefix CSS classes with ld- and use BEM.
• Stylesheet files of WebComponents which have no CSS Component counterpart must include a .shadow suffix in the file name (for instance ld-sidenav.shadow.css). This will ensure the CSS does not end up in the CSS components bundle.
• When writing CSS, we follow common best practices. We try to keep the CSS specificity to a minimum, in order to simplify component customization, but we also make sure that it is not low to an extent, where styles get overwritten by other librariesapos; reset or normalize styles (such as Tailwindapos;s Preflight). In other words: If you are using the CSS :where trick to reduce CSS speceficity to zero, make sure the properties affected are not potential candidates for reset and normalize styles.
• Due to an issue in Stencil, type declarations need to be either inlined or exported, as otherwise undefined types end up in the generated components.d.ts file.
• A lists of all labels we use in order to help us track and manage issues and pull requests can be found here.

We also use husky for running Git hooks which in turn run lint tasks before you commit or push something. Which brings us to the next point...

Commit messages #

Commit messages are linted with commitlint and should adhere to the Conventional Commits specification. This ensures that semantic release, which we use for automated release management, works as it is supposed to. Please squash commits which together solve a specific task before submitting a pull request. This not only ensures a clean Git history, but also a clean changelog which is generated by semantic release automatically upon release.

Branch names #

Branch names are linted using the following regular expression before push:

^((feat|fix|hotfix|build|chore|ci|docs|style|refactor|perf|test)\/([a-z0-9._-]+)|main|rc)$

How to run tests #

There are multiple commands available as npm scripts for running different kinds of tests: Unit tests, functional (e2e) tests as well as visual regression tests (using screenshots) are handled by Stencil. We also run accessibility tests within the functional test suits using axe-core.

You execute tests either by running one of the npm scripts which start with test (see package.json) or by executing the respective test commands directly with the options needed. Please refer to the docs of each test runner in question for available options.

The following examples should help you start testing quickly and efficiently.

Run all unit tests with coverage: #

yarn test:unit

Run all unit tests in watch mode: #

yarn test:watch

Run unit tests for the ld-tabs component in watch mode with coverage: #

stencil test --spec --coverage --no-cache --watch=all -- ld-tabs ld-tablist

Run all end-to-end tests: #

yarn test:e2e

Run end-to-end tests for the ld-sidenav component: #

stencil test --screenshot --e2e -- src/liquid/components/ld-sidenav/test/ld-sidenav.e2e.ts && yarn test:e2e:cleanup

Compare visual regression testing screenshots of failed end-to-end tests: #

yarn test:compare_screenshots

Delete all visual regression testing screenshots for the ld-sidenav component: #

ts-node scripts/screenshots.ts rm -c ld-sidenav

Pull requests #

When you have implemented changes in your local clone or fork of our Liquid Oxygen repository, it is time to create a pull request in order to integrate these changes. But before you do that, please follow these steps to make sure your contribution gets considered by the Liquid Oxygen maintainers:

1. Be sure you follow all instructions in the template.
2. Be sure you follow the project conventions.
3. After you submit your pull request, verify that all status checks are passing. If a status check is failing, and you believe that the failure is unrelated to your change, please leave a comment on the pull request explaining why you believe the failure is unrelated. A maintainer will re-run the status check for you. If we conclude that the failure was a false positive, we will open an issue to track that problem with our status check suite.

While the prerequisites above must be satisfied prior to having your pull request reviewed, the reviewer(s) may ask you to complete additional design work, tests, or other changes before your pull request can be ultimately accepted.

Where to go from here #

If you want to dive deeper into the technology stack used in the Liquid Oxygen project, check out the below list of selected documentation sites and articles we found valuable:

• https://stenciljs.com
• https://www.11ty.dev
• https://postcss.org
• https://jestjs.io
• https://pptr.dev
• https://github.com/dequelabs/axe-core
• https://yarnpkg.com
• https://semantic-release.gitbook.io
• https://www.conventionalcommits.org
• https://developer.mozilla.org/en-US/docs/Web/Web_Components
• https://dev.to/richharris/why-i-don-t-use-web-components-2cia
• https://custom-elements-everywhere.com
• http://getbem.com/introduction
• https://webaim.org/articles/screenreader_testing

Let us know if we should add something! 🤓