React Native Animations

React Native Animations Skill

Learn high-performance animations using Reanimated 3, Gesture Handler, and layout animations.

Prerequisites

• React Native basics
• Understanding of JavaScript closures
• Familiarity with transforms and styles

Learning Objectives

After completing this skill, you will be able to:

• [ ] Create smooth 60fps animations with Reanimated
• [ ] Handle complex gestures with Gesture Handler
• [ ] Implement layout entering/exiting animations
• [ ] Optimize animations for performance
• [ ] Combine gestures with animations

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Topics Covered

1. Installation

npm install react-native-reanimated react-native-gesture-handler

# babel.config.js
module.exports = {
  plugins: ['react-native-reanimated/plugin'],
};

2. Reanimated Basics

import Animated, {
  useSharedValue,
  useAnimatedStyle,
  withSpring,
} from 'react-native-reanimated';

function AnimatedBox() {
  const scale = useSharedValue(1);

  const animatedStyle = useAnimatedStyle(() => ({
    transform: [{ scale: scale.value }],
  }));

  const handlePress = () => {
    scale.value = withSpring(scale.value === 1 ? 1.5 : 1);
  };

  return (
    <Pressable onPress={handlePress}>
      <Animated.View style={[styles.box, animatedStyle]} />
    </Pressable>
  );
}

3. Gesture Handler

import { Gesture, GestureDetector } from 'react-native-gesture-handler';

function DraggableBox() {
  const translateX = useSharedValue(0);
  const translateY = useSharedValue(0);

  const pan = Gesture.Pan()
    .onUpdate((e) => {
      translateX.value = e.translationX;
      translateY.value = e.translationY;
    })
    .onEnd(() => {
      translateX.value = withSpring(0);
      translateY.value = withSpring(0);
    });

  const style = useAnimatedStyle(() => ({
    transform: [
      { translateX: translateX.value },
      { translateY: translateY.value },
    ],
  }));

  return (
    <GestureDetector gesture={pan}>
      <Animated.View style={[styles.box, style]} />
    </GestureDetector>
  );
}

4. Layout Animations

import Animated, { FadeIn, FadeOut, Layout } from 'react-native-reanimated';

function AnimatedList({ items }) {
  return (
    <Animated.View layout={Layout.springify()}>
      {items.map((item) => (
        <Animated.View
          key={item.id}
          entering={FadeIn}
          exiting={FadeOut}
          layout={Layout.springify()}
        >
          <Text>{item.title}</Text>
        </Animated.View>
      ))}
    </Animated.View>
  );
}

5. Animation Timing

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Quick Start Example

import Animated, {
  useSharedValue,
  useAnimatedStyle,
  withSpring,
  interpolate,
} from 'react-native-reanimated';
import { Gesture, GestureDetector } from 'react-native-gesture-handler';

function SwipeCard() {
  const translateX = useSharedValue(0);

  const gesture = Gesture.Pan()
    .onUpdate((e) => { translateX.value = e.translationX; })
    .onEnd(() => { translateX.value = withSpring(0); });

  const style = useAnimatedStyle(() => ({
    transform: [
      { translateX: translateX.value },
      { rotate: `${interpolate(translateX.value, [-200, 200], [-15, 15])}deg` },
    ],
  }));

  return (
    <GestureDetector gesture={gesture}>
      <Animated.View style={[styles.card, style]} />
    </GestureDetector>
  );
}

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Common Errors & Solutions

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Validation Checklist

• [ ] Animations run at 60fps
• [ ] Gestures respond smoothly
• [ ] No frame drops on low-end devices
• [ ] Layout animations don't cause jank

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Usage

Skill("react-native-animations")

Bonded Agent: 05-react-native-animation

React Native Animations Guide

Overview

This guide provides comprehensive documentation for the react-native-animations skill in the custom-plugin-react-native plugin.

Category: General

Quick Start

Prerequisites

• Familiarity with general concepts
• Development environment set up
• Plugin installed and configured

Basic Usage

# Invoke the skill
claude "react-native-animations - [your task description]"

# Example
claude "react-native-animations - analyze the current implementation"

Core Concepts

Key Principles

1. Consistency - Follow established patterns 2. Clarity - Write readable, maintainable code 3. Quality - Validate before deployment

Best Practices

• Always validate input data
• Handle edge cases explicitly
• Document your decisions
• Write tests for critical paths

Common Tasks

Task 1: Basic Implementation

# Example implementation pattern
def implement_react_native_animations(input_data):
    """
    Implement react-native-animations functionality.

    Args:
        input_data: Input to process

    Returns:
        Processed result
    """
    # Validate input
    if not input_data:
        raise ValueError("Input required")

    # Process
    result = process(input_data)

    # Return
    return result

Task 2: Advanced Usage

For advanced scenarios, consider:

• Configuration customization via assets/config.yaml
• Validation using scripts/validate.py
• Integration with other skills

Troubleshooting

Common Issues

Related Resources

• SKILL.md - Skill specification
• config.yaml - Configuration options
• validate.py - Validation script

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Last updated: 2025-12-30

React Native Animations Patterns

Design Patterns

Pattern 1: Input Validation

Always validate input before processing:

def validate_input(data):
    if data is None:
        raise ValueError("Data cannot be None")
    if not isinstance(data, dict):
        raise TypeError("Data must be a dictionary")
    return True

Pattern 2: Error Handling

Use consistent error handling:

try:
    result = risky_operation()
except SpecificError as e:
    logger.error(f"Operation failed: {e}")
    handle_error(e)
except Exception as e:
    logger.exception("Unexpected error")
    raise

Pattern 3: Configuration Loading

Load and validate configuration:

import yaml

def load_config(config_path):
    with open(config_path) as f:
        config = yaml.safe_load(f)
    validate_config(config)
    return config

Anti-Patterns to Avoid

❌ Don't: Swallow Exceptions

# BAD
try:
    do_something()
except:
    pass

✅ Do: Handle Explicitly

# GOOD
try:
    do_something()
except SpecificError as e:
    logger.warning(f"Expected error: {e}")
    return default_value

Category-Specific Patterns: General

Recommended Approach

1. Start with the simplest implementation 2. Add complexity only when needed 3. Test each addition 4. Document decisions

Common Integration Points

• Configuration: assets/config.yaml
• Validation: scripts/validate.py
• Documentation: references/GUIDE.md

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Pattern library for react-native-animations skill