Seeds – Component Library for Bloom

This package serves as the home of Bloom's core UI components, meant to be imported from within various applications. Seeds supersedes Bloom's previous "ui-components" package.

Seeds is built using TypeScript, React, and Sass. It uses Storybook for concrete component examples and Jest for testing.

Design System Documentation

We use zeroheight to document tokens, components, and patterns for the Seeds Design System.

For code-level changes over time, see GitHub Releases for Changelog.

Usage

Next.js

To get Seeds set up, first add the @bloom-housing/ui-seeds package via npm or yarn. Next, update next.config.js to include the package name in its transpilePackages config option:

  transpilePackages: [
    "@bloom-housing/ui-seeds"
  ]

You will need to have Sass & PostCSS installed, along with the @csstools/postcss-global-data & postcss-custom-media packages. Ensure they are available via the postcss.config.js file:

  plugins: {
    "@csstools/postcss-global-data": {
      // in the Bloom monorepo, this starts with `../../`:
      files: ["node_modules/@bloom-housing/ui-seeds/src/global/tokens/screens.scss"],
    },
    "postcss-custom-media": {},
    ...
  }

Finally, import the primary CSS entrypoint for Seeds in your _app.tsx file:

import "@bloom-housing/ui-seeds/src/global/app-css.scss"

Now you can import individual Seeds React components on the pages where you need to use them.

Contributing

Seeds is comprised primarily of design tokens and components. There are a handful of global style rules and utility classes, but they are intentionally kept to a minimum. Component-scoped style rules whenever possible are preferable.

For design tokens, component classes, and utility classes, it is generally recommended to start with the seeds prefix.

Design Tokens

Design tokens are broken out into two layers: base tokens and semantic tokens. Semantic tokens consume the base tokens. Whenever possible, components should rely on semantic tokens rather than base tokens. This will allow for easy customization of the theme downstream (consumers are encouraged to override semantic tokens, not base tokens).

For example, --seeds-color-blue-500 is set to #0077da. In addition, --seeds-color-primary is set to var(--seeds-color-blue-500). Your component should utilize --seeds-color-primary rather than --seeds-color-blue-500, unless you know for certain you always need to use that particular color regardless of downstream theme changes.

Components are encouraged to set up their own component-specific tokens, which can leverage both semantic or base tokens (when a suitable semantic token isn't available). For example:

.seeds-card {
  --card-spacing-md: var(--seeds-s6); /* a base token */
  --card-background-color: var(--seeds-bg-color-surface); /* a semantic token */
}

Various parts/subcomponents within a component many consume component tokens which have been defined at this top-level.

We don't encourage defining tokens below the top-level, as consumers would then have to know about the internal DOM structure of a component which is bad for future-compatibility.

/* Bad */
.seeds-component {
  --component-token-1: var(--seeds-s3);

  padding: var(--component-token-1);

  > .seeds-component-section {
    --component-token-2: var(--seeds-s5);

    padding: var(--component-token-2);
  }
}

/* Good */
.seeds-component {
  --component-token-1: var(--seeds-s3);
  --component-section-token-1: var(--seeds-s5);

  > .seeds-component-section {
    padding: var(--component-section-token-1);
  }
}

Component Definitions

Components are built as functional React components, with filenames to match the component name. So FieldValue.tsx exports a component named FieldValue. Component files are located next to "sidecar" .scss files containing styles for the component.

A component class is a kebab-cased name of the component prefixed with seeds. So the FieldValue component would associated with the seeds-field-value class name.

Components may offer many variations such as color/type variants, sizes, etc. It is encouraged to use data-* attributes in your HTML to specify these variations:

<span
  id={props.id}
  className={classNames.join(" ")}
  data-variant={props.variant || "primary"}
  data-size={props.size}
  aria-label={props.ariaLabel}
>
  {props.children}
</span>

Then in your stylesheet, you can add style rules based on these attributes:

.seeds-tag {
  &[data-variant="primary"] {
    background-color: var(--seeds-color-primary-light);
    color: var(--seeds-color-primary-dark);
  }

  &[data-size="lg"] {
    font-size: var(--tag-font-size-lg);
    font-weight: var(--tag-font-weight-lg);
  }
}

Some boolean-style variations or "states" are more straightforward to do as conditional classes. In that case, we typically use is- or has- prefixes, e.g. .is-fullwidth or .has-lead-icon.

Some states are also better expressed through the use of ARIA roles and attributes. If ARIA needs to be managed through the HTML markup anyway, it's best to hang styles off of those instead of introducing duplication through additional attributes/classes.

Documentation

Storybook stories are written in the __stories__ folders in .stories.tsx files. These stories can then be displayed in documentation within zeroheight.

In addition, the .docs.mdx files will provide a display of props and styling information.

Component props are documented using TypeScript interfaces along with JSDoc comments. These comments will show up in Storybook when using the ArgsTable component in the MDX files.

Component tokens are also documented using a Markdown table in the story MDX files.

In zeroheight, stories can easily be embedded one-by-one due to the integration which was set up. However, to embed the props/styles docs pages, you will need to open up Storybook, click the "Docs" tab for a component, and copy the URL to an "iframe" embed within zeroheight.

Testing

Unit tests are located within __tests__ folders, written with React's Testing Library and executed via Jest. Unit tests are intended to verify the basic functionality of a component along with any major branches in display logic.