Core Components

When to Use

Use this skill when you need core component library and design system patterns. Use when building UI, using design tokens, or working with the component library.

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

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

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

| Token | Value | |-------|-------| | $1 | 4px | | $2 | 8px | | $3 | 12px | | $4 | 16px | | $6 | 24px | | $8 | 32px |

Color Tokens

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

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

| Semantic Token | Use For | |----------------|---------| | $textPrimary | Main text | | $textSecondary | Supporting text | | $textTertiary | Disabled/hint text | | $primary500 | Brand/accent color | | $statusError | Error states | | $statusSuccess | Success states |

Typography Tokens

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

| Token | Size | |-------|------| | $xs | 12px | | $sm | 14px | | $md | 16px | | $lg | 18px | | $xl | 20px | | $2xl | 24px |

Core Components

Box

Base layout component with token support:

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

HStack / VStack

Horizontal and vertical flex layouts:

tsx
<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:

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

Button

Interactive button with variants:

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

| Variant | Use For | |---------|---------| | solid | Primary actions | | outline | Secondary actions | | ghost | Tertiary/subtle actions | | link | Inline actions |

Input

Form input with validation:

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

Card

Content container:

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

Layout Patterns

Screen Layout

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

Form Layout

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

List Item Layout

tsx
<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

tsx
// 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:

tsx
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

Limitations

• Use this skill only when the task clearly matches its upstream source and local project context.
• Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes.
• Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.