4. Creating components – Carbon Design System

With two pages comprised entirely of Carbon components, let’s revisit the landing page and build a couple components of our own by using Carbon icons and tokens.

Fork, clone and branch
Review design
Create components
Use components
Add styling
Check accessibility
Submit pull request

Preview

Carbon provides a solid foundation for building web applications through its color palette, layout, spacing, type, as well as common building blocks in the form of components. So far, we’ve only used Carbon components to build out two pages.

Next, we’re going to use Carbon assets to build application-specific components. We’ll do so by including accessibility and responsive considerations all throughout.

A preview of what you’ll build (see bottom of page):

Fork, clone and branch

This tutorial has an accompanying GitHub repository called carbon-tutorial that we’ll use as a starting point for each step. If you haven’t forked and cloned that repository yet, and haven’t added the upstream remote, go ahead and do so by following the step 1 instructions.

Branch

With your repository all set up, let’s check out the branch for this tutorial step’s starting point.

git fetch upstream
git checkout -b vue-step-4 upstream/vue-step-4

Note: This builds on top of step 3, but be sure to check out the upstream step 4 branch because it includes the static assets required to get through this step.

Build and start app

Install the app’s dependencies (in case you’re starting fresh in your current directory and not continuing from the previous step):

yarn

Then, start the app:

yarn serve

You should see something similar to where the previous step left off.

Review design

Here’s what we’re building – an informational section that has a heading and three subheadings. Each subheading has accompanying copy and a pictogram. We’ll assume that this informational section is used elsewhere on the site, meaning it’s a great opportunity to build it as a reusable component. As for naming, we’ll call it an InfoSection with three InfoCards as children.

Info section layout

Create components

First we need files for the components, so create an InfoSection folder in src/components. Even though we’re building multiple components, their names all start with Info, so it makes sense to have them share one folder in components. Create these files:

Add files

src/components/InfoSection
├──index.js
└──InfoCard.vue
└──InfoSection.vue

Like our other components, index.js will serve as an entrypoint.

Note: To adhere to the Vue style guide we have used multi word component names. This style guide stipulation is why all @carbon/vue components have a cv prefix.

src/components/InfoSection/index.js
import InfoSection from './InfoSection';
import InfoCard from './InfoCard';
export { InfoSection, InfoCard };

InfoSection component

Let’s create the parent component that includes the “The Principles” heading. That markup currently looks like this in LandingPage.vue:

src/views/LandingPage/LandingPage.vue
<div class="bx--row landing-page__r3">
  <div class="bx--col-md-4 bx--col-lg-4">
    <h3 class="landing-page__label">The Principles</h3>
  </div>
  <div class="bx--col-md-4 bx--col-lg-4">Carbon is Open</div>
  <div class="bx--col-md-4 bx--col-lg-4">Carbon is Modular</div>
  <div class="bx--col-md-4 bx--col-lg-4">Carbon is Consistent</div>
</div>

We want to do a few things when abstracting it to a component. First, we only want Carbon (bx--) and this component’s class names; we don’t want to include landing-page__r3 as that’s specific to the landing page. That will be passed in as a property to the component.

We’ll also:

Add component class names like info-section and info-section__heading
Semantically use <section> instead of <div>
Update the grid columns to match the design
Replace The Principles with {{heading}}
Replace columns 2 - 4 with a slot.

Using props we can render any heading and any number of children components (InfoCard that we’ll build soon.)

src/components/InfoSection/InfoSection.vue
<template>
  <section class="bx--row info-section">
    <div class="bx--col-md-8 bx--col-lg-4 bx--col-xlg-3">
      <h3 class="info-section__heading">{{ heading }}</h3>
    </div>
    <slot />
  </section>
</template>

Then name our component and add a property to the script section.

src/components/InfoSection/InfoSection.vue
<script>
export default {
  name: "InfoSection",
  props: {
    heading: String
  }
};
</script>

At this point let’s add styling for the new class names that we just added.

src/components/InfoSection/InfoSection.vue
<style lang="scss">
@import "../../styles/_carbon-utils";
.info-section__heading {
  @include carbon--type-style('heading-01');
}
</style>

InfoCard component

Next up we’re going to build a component for columns 2 - 4, which currently looks like <div class="bx--col-md-4 bx--col-lg-4">Carbon is Open</div>. Create a new file InfoCard.vue, add:

src/components/InfoSection/InfoCard.vue
<template>
  <article
    class="info-card bx--col-md-4 bx--col-lg-4 bx--col-xlg-3 bx--offset-xlg-1"
  >
    <h4 class="info-card__heading">{{ heading }}</h4>
    <p class="info-card__body">{{ body }}</p>
    <component :is="icon" />
  </article>
</template>

Give it a name and add props

<script>
export default {
  name: "InfoCard",
  props: {
    heading: String,
    body: String,
    icon: Object
  }
};

Note: Make sure to export the two components from index.js!

In doing so, we:

Used the semantic <article> instead of <div>
Added info-card classes
Used props to render the heading, body copy, and icon
Set columns to match the grid

Note: At extra large viewports, we are using bx--col-xlg-3 bx--offset-xlg-1 so each column takes up 3 of the 16 grid columns, with a 1 column offset.

Use components

Our styling is not complete yet, but with our components built let’s put them to use. In LandingPage.vue, import the components towards the top of the script section. If you haven’t added a script section, do so now.

src/views/LandingPage/LandingPage.vue
<script>
import { InfoSection, InfoCard } from '../../components/InfoSection';
export default {
  name: 'LandingPage',
  components: { InfoSection, InfoCard }
};
</script>

While we’re here next to the component imports, let’s import the icons that we’ll need as well.

src/views/LandingPage/LandingPage.vue
import Globe32 from '@carbon/icons-vue/lib/globe/32';
import PersonFavorite32 from '@carbon/icons-vue/lib/person--favorite/32';
import Application32 from '@carbon/icons-vue/lib/application/32';

Note: You’ll notice that these 32px icons aren’t the pictograms as designed. The Carbon team is currently working on adding pictograms to the icons packages. Until then, we’ll use the biggest SVGs.

Don’t forget to add the icons to the list of components used in our template. Wait a minute, are they being used by our template? Well, yes and no. The components are going to be passed as an attribute rather than being used as a DOM element. Vue treats this use case differently and instead of adding to the components property, we need to assign the icons directly to the this object. We can achieve this in a number of different ways, for example as data or computed properties. The following is our preferred method when reactivity is not needed.

In the script section of the component add the lifecycle method created() to add the icons to the component.

src/views/LandingPage/LandingPage.vue
  created() {
    // Add icons to this
    Object.assign(this, {
      Globe32,
      PersonFavorite32,
      Application32
    });
  }

With everything imported, replace the current template content:

src/views/LandingPage/LandingPage.vue
<div class="bx--row landing-page__r3">
  <div class="bx--col-md-4 bx--col-lg-4">
    <h3 class="landing-page__label">The Principles</h3>
  </div>
  <div class="bx--col-md-4 bx--col-lg-4">Carbon is Open</div>
  <div class="bx--col-md-4 bx--col-lg-4">Carbon is Modular</div>
  <div class="bx--col-md-4 bx--col-lg-4">Carbon is Consistent</div>
</div>

With the new components:

src/views/LandingPage/LandingPage.vue
<info-section heading="The Principles" class="landing-page__r3">
</info-section>

Then slot the InfoCard content inside the InfoSection tag to give.

src/views/LandingPage/LandingPage.vue
<info-section heading="The Principles" class="landing-page__r3">
  <info-card
    heading="Carbon is Open"
    body="It's a distributed effort, guided by the principles of the open-source movement. Carbon's users are also it's makers, and everyone is encouraged to contribute."
    :icon="PersonFavorite32"
  />
  <info-card
    heading="Carbon is Modular"
    body="Carbon's modularity ensures maximum flexibility in execution. It's components are designed to work seamlessly with each other, in whichever combination suits the needs of the user."

Note: Now is a good time to resize your browser from phone to extra large viewport widths to see how the responsive grid is working before we add further styling.

Add styling

Here’s our design showing the spacing tokens that we need to add. We also need to set the type style and borders.

Info section spacing

Layout

Starting with layout, add the style section to src/components/InfoSection/InfoCard.vue.

src/components/InfoSection/InfoCard.vue
<style lang="scss">
@import "../../styles/carbon-utils";
.info-card {
  margin-top: $spacing-09;
  display: flex;
  flex-direction: column;
  svg {

Once you save, go ahead and resize your browser to see the responsive layout at the different breakpoints. Make sure to review these color and spacing tokens. There are also a few breakpoint mixins that may be new to you.

Type

Our InfoCard headings look to be too small. We need to increase their font sizes according to the design spec with:

src/components/InfoSection/InfoCard.vue
.info-card__heading {
  @include carbon--type-style('productive-heading-03');
}

Also, the design has the last word in each subheading as bold. To accomplish that, add this computed property to InfoCard.vue.

src/components/InfoSection/InfoCard.vue
computed: {
  // Take in a phrase and separate the third word in an array
  splitHeading() {
    const splitHeading = this.heading.split(" ");
    const finalWord = splitHeading.pop();
    return [splitHeading.join(" "), finalWord];
  }
}

Then, update InfoCard.vue to use splitHeading.

Replacing

src/components/InfoSection/InfoCard.vue
<h4 class="info-card__heading">{{heading}}</h4>

with

src/components/InfoSection/InfoCard.vue
<h4 class="info-card__heading">
  {{ splitHeading[0] }}
  <strong>{{ splitHeading[1] }}</strong>
</h4>

Finally, add the following declaration block in the style section of InfoCard.vue to set body copy styles and to bottom-align the icons.

src/components/InfoSection/InfoCard.vue
.info-card__body {
  margin-top: $spacing-06;
  flex-grow: 1; // fill space so icons are bottom aligned
  @include type-style('body-long-01');
  // prevent large line lengths between small and medium viewports
  @include carbon--breakpoint-between(321px, md) {
    max-width: 75%;
  }

Check accessibility

We’ve added new markup and styles, so it’s a good practice to check DAP and make sure our rendered markup is on the right track for accessibility.

With the browser extension installed, Chrome in this example, open Dev Tools and run DAP.

DAP violations

That first violation is for the off-screen “skip to content” link. This link isn’t shown and is used to assist screen reading, so the color contrast violation can be ignored.

But, those three other violations came from the <article> element used in new InfoCard. Since the <article> element requires a label, it seems like we may be using the wrong semantic element. A humble <div> will suffice.

In InfoCard.vue, replace the <article> opening and closing tags with <div> tags.

Also it’s time to fix it if you didn’t but I’m sure you can manage that by yourself.

Submit pull request

We’re going to submit a pull request to verify completion of this tutorial step.

Continuous integration (CI) check

Run the CI check to make sure we’re all set to submit a pull request.

yarn ci-check

Note: Having issues running the CI check? Step 1 has troubleshooting notes that may help.

Git commit and push

Before we can create a pull request, stage and commit all of your changes:

git add --all && git commit -m "feat(tutorial): complete step 4"

Then, push to your repository:

git push origin vue-step-4

Note: Having issues pushing your changes? Step 1 has troubleshooting notes that may help.

Pull request (PR)

Finally, visit carbon-tutorial to “Compare & pull request”. In doing so, make sure that you are comparing to vue-step-4 into base: vue-step-4.

Note: Expect your tutorial step PRs to be reviewed by the Carbon team but not merged. We’ll close your PR so we can keep the repository’s remote branches pristine and ready for the next person!

Edit this page on GitHub

Vue tutorial: Step 3

Vue tutorial: Step 5