Core Components

Core Components

Design System Overview

Use components from your core library instead of raw platform components. This ensures consistent styling and behavior.

Design Tokens

NEVER hard-code values. Always use design tokens.

Spacing Tokens

// CORRECT - Use tokens
<Box padding="$4" marginBottom="$2" />

// WRONG - Hard-coded values
<Box padding={16} marginBottom={8} />

Color Tokens

// CORRECT - Semantic tokens
<Text color="$textPrimary" />
<Box backgroundColor="$backgroundSecondary" />

// WRONG - Hard-coded colors
<Text color="#333333" />
<Box backgroundColor="rgb(245, 245, 245)" />

Typography Tokens

<Text fontSize="$lg" fontWeight="$semibold" />

Core Components

Box

Base layout component with token support:

<Box
  padding="$4"
  backgroundColor="$backgroundPrimary"
  borderRadius="$lg"
>
  {children}
</Box>

HStack / VStack

Horizontal and vertical flex layouts:

<HStack gap="$3" alignItems="center">
  <Icon name="user" />
  <Text>Username</Text>
</HStack>

<VStack gap="$4" padding="$4">
  <Heading>Title</Heading>
  <Text>Content</Text>
</VStack>

Text

Typography with token support:

<Text
  fontSize="$lg"
  fontWeight="$semibold"
  color="$textPrimary"
>
  Hello World
</Text>

Button

Interactive button with variants:

<Button
 
  variant="solid"
  size="md"
  isLoading={loading}
  isDisabled={disabled}
>
  Click Me
</Button>

Input

Form input with validation:

<Input
  value={value}
 
  placeholder="Enter text"
  error={touched ? errors.field : undefined}
  label="Field Name"
/>

Card

Content container:

<Card padding="$4" gap="$3">
  <CardHeader>
    <Heading size="sm">Card Title</Heading>
  </CardHeader>
  <CardBody>
    <Text>Card content</Text>
  </CardBody>
</Card>

Layout Patterns

Screen Layout

const MyScreen = () => (
  <Screen>
    <ScreenHeader title="Page Title" />
    <ScreenContent padding="$4">
      {/* Content */}
    </ScreenContent>
  </Screen>
);

Form Layout

<VStack gap="$4" padding="$4">
  <Input label="Name" {...nameProps} />
  <Input label="Email" {...emailProps} />
  <Button isLoading={loading}>Submit</Button>
</VStack>

List Item Layout

<HStack
  padding="$4"
  gap="$3"
  alignItems="center"
  borderBottomWidth={1}
  borderColor="$borderLight"
>
  <Avatar source={{ uri: imageUrl }} size="md" />
  <VStack flex={1}>
    <Text fontWeight="$semibold">{title}</Text>
    <Text color="$textSecondary" fontSize="$sm">{subtitle}</Text>
  </VStack>
  <Icon name="chevron-right" color="$textTertiary" />
</HStack>

Anti-Patterns

// WRONG - Hard-coded values
<View style={{ padding: 16, backgroundColor: '#fff' }}>

// CORRECT - Design tokens
<Box padding="$4" backgroundColor="$backgroundPrimary">


// WRONG - Raw platform components
import { View, Text } from 'react-native';

// CORRECT - Core components
import { Box, Text } from 'components/core';


// WRONG - Inline styles
<Text style={{ fontSize: 18, fontWeight: '600' }}>

// CORRECT - Token props
<Text fontSize="$lg" fontWeight="$semibold">

Component Props Pattern

When creating components, use token-based props:

interface CardProps {
  padding?: '$2' | '$4' | '$6';
  variant?: 'elevated' | 'outlined' | 'filled';
  children: React.ReactNode;
}

const Card = ({ padding = '$4', variant = 'elevated', children }: CardProps) => (
  <Box
    padding={padding}
    backgroundColor="$backgroundPrimary"
    borderRadius="$lg"
    {...variantStyles[variant]}
  >
    {children}
  </Box>
);

Integration with Other Skills

• react-ui-patterns: Use core components for UI states
• testing-patterns: Mock core components in tests
• storybook: Document component variants

When to Use

This skill is applicable to execute the workflow or actions described in the overview.

🏰 Rei Skills — Curated by Rootcastle Engineering & Innovation | Batuhan Ayrıbaş
Engineering Beyond Boundaries | admin@rootcastle.com