Component Guide

Component Guide

Before Building Anything Custom

Check if @stellar/design-system already has the component: https://github.com/stellar/stellar-design-system

For the full component catalog (SDS + local layout wrappers) and props patterns, see reference/ui-components.md (loaded automatically).

Component File Structure

With styles (preferred for non-trivial components)

src/components/ComponentName/
├── index.tsx
└── styles.scss

Without styles (simple components)

src/components/ComponentName.tsx

Page-specific components

src/app/(sidebar)/[feature]/components/ComponentName.tsx

Component Template

"use client";

import { useState } from "react";
import { Button, Input, Card } from "@stellar/design-system";

import "./styles.scss";

interface ComponentNameProps {
  /** Description of prop */
  propName: string;
}

/**
 * Brief description of what this component does
 *
 * @example
 * <ComponentName propName="value" />
 */
export const ComponentName = ({ propName }: ComponentNameProps) => {
  return (
    <div className="ComponentName">
      <div className="ComponentName__header">
        {/* ... */}
      </div>
      <div className="ComponentName__content">
        {/* ... */}
      </div>
    </div>
  );
};

SCSS Template

.ComponentName {
  // Root styles

  &__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  &__content {
    display: flex;
    flex-direction: column;
    gap: pxToRem(16px);
  }

  &__footer {
    display: flex;
    gap: pxToRem(8px);
  }
}

Conventions

Do

• Use design system components for all standard UI elements
• Use SCSS with BEM-ish class naming (ComponentName__element--modifier)
• Use pxToRem() for spacing values in SCSS (skip for trivial values like 1px or -1px — e.g., borders, outlines, offsets — where rem scaling is not meaningful)
• Use SDS CSS custom properties for colors/fonts/gaps: var(--sds-clr-gray-06), var(--sds-ff-monospace), var(--sds-gap-md)
• Use data-* attributes for state-driven styling instead of modifier classes: data-is-active, data-is-visible, data-is-selected, data-is-clickable
• Use data-testid with dashes for test selectors (data-testid="sign-button")
• Add JSDoc comments with @example for exported components
• Co-locate page-specific components with their page
• Import shared SCSS utilities: @use "../../styles/utils.scss" as *;

Don't

• Use inline style={} attributes — always use SCSS classes
• Create custom buttons, inputs, or alerts when design system has equivalents
• Use arbitrary hex colors — use SDS CSS custom properties (--sds-clr-*)
• Put styles in the component file — always separate into .scss
• Use className string concatenation — use template literals or classnames lib
• Use conditional CSS classes for state — prefer data-* attributes

Data Attribute Pattern for State-Driven Styling

Prefer data-* attributes over CSS modifier classes for dynamic state:

// Component
<div
  className="TransactionStepper__step"
  data-is-active={isActive || undefined}
  data-is-completed={isCompleted || undefined}
  data-is-clickable={isClickable || undefined}
  ? () => onStepClick(step) : undefined}
>

// SCSS — target with attribute selectors
.TransactionStepper__step {
  opacity: 0.5;

  &[data-is-active="true"] {
    opacity: 1;
    font-weight: var(--sds-fw-medium);
  }

  &[data-is-clickable="true"] {
    cursor: pointer;
  }

  &[data-is-completed="true"] {
    opacity: 0.8;
  }
}

Pass undefined (not false) to omit the attribute from the DOM entirely.