Component Composition

Component Composition Overview

Component Composition lets you structure design systems work so it stays readable, testable, and easy to scale. Instead of ad-hoc code, you follow a clear pattern that other developers can recognise immediately.

The key is to keep component composition focused and predictable. Start from the minimal example here, then layer in only the complexity your feature actually needs.

<ds-card>
  <h3 slot="title">Plan</h3>
  <p slot="body">Everything your team needs.</p>
  <ds-button slot="actions" variant="primary">Choose</ds-button>
</ds-card>

Slot-based composition lets consumers place content while the component controls structure and style.

Component Composition Example

/* Tokens flow into components, which flow into products */
:root { --color-brand-500: #2563eb; }
.button { background: var(--color-brand-500); }

• Start from a minimal Component Composition example and grow it only as needed.
• Keep configuration explicit so Component Composition behaves the same in every environment.
• Name things clearly so teammates understand your Component Composition at a glance.
• Add tests around Component Composition early to lock in expected behaviour.

Design System Cheatsheet

Quick reference for component composition within a modern design system.

How Component Composition Fits into a Design System

Component Composition connects the design decisions in your system to the code teams actually ship. When it is defined once and reused, products stay consistent and updates roll out everywhere.

Slot-based composition lets consumers place content while the component controls structure and style.

• Define it once as a token or shared component.
• Document intended usage with clear examples.
• Make it themeable and accessible by default.
• Version and release changes so consumers can upgrade safely.

Getting Teams to Adopt Component Composition

Adoption is where design systems succeed or stall. Make component composition the easiest option: great docs, sensible defaults, and clear migration paths beat mandates every time.

Common Mistakes

• Copying component composition snippets without understanding what each line does.
• Skipping error handling and edge cases when wiring up component composition.
• Leaving component composition untested, so regressions slip into production.
• Over-engineering component composition before you actually need the extra flexibility.

Key Takeaways

• Component Composition is a core part of working effectively with design systems.
• Start small and keep component composition focused on a single responsibility.
• Apply consistent patterns so component composition scales across your project.
• Test and document component composition to keep it maintainable over time.