Scan for Animated/Reanimated code and migrate to EaseView
---
name: react-native-ease-refactor
description: Scan for Animated/Reanimated code and migrate to EaseView
user-invocable: true
---
# react-native-ease refactor
You are a migration assistant that converts `react-native-reanimated` and React Native's built-in `Animated` API code to `react-native-ease` `EaseView` components.
Follow these 6 phases exactly. Do not skip phases or reorder them.
---
## Phase 1: Discovery
Scan the user's project for animation code:
1. Use Grep to detect if the project uses NativeWind:
- Pattern: `from ['"]nativewind['"]` in `**/*.{ts,tsx,js,jsx}`
- Also check `package.json` for `"nativewind"` in dependencies
- If NativeWind is detected, set a flag `usesNativeWind = true` for use in Phase 5
2. Detect the Reanimated version (needed for default value mapping in Phase 2):
- Read `package.json` and check the `react-native-reanimated` version in `dependencies` or `devDependencies`
- If the version is `^4` or `>=4.0.0`, set `reanimatedVersion = 4`
- Otherwise set `reanimatedVersion = 3` (covers v2/v3 which share the same defaults)
3. Use Grep to find all files importing from `react-native-reanimated`:
- Pattern: `from ['"]react-native-reanimated['"]`
- Search in `**/*.{ts,tsx,js,jsx}`
4. Use Grep to find all files using React Native's built-in `Animated` API:
- Pattern: `from ['"]react-native['"]` that also use `Animated`
- Pattern: `Animated\.View|Animated\.Text|Animated\.Image|Animated\.Value|Animated\.timing|Animated\.spring`
3. Use Grep to find files already using `react-native-ease` (to avoid re-migrating):
- Pattern: `from ['"]react-native-ease['"]`
4. Read each file that contains animation code. Build a list of components with their animation patterns.
**Exclude** from scanning:
- `node_modules/`
- `*.test.*` and `*.spec.*` files
- Build output directories (`lib/`, `build/`, `dist/`)
---
## Phase 2: Classification
For each component found, classify as **migratable** or **not migratable**.
### Decision Tree
Apply these checks in order. The first match determines the result:
1. **Uses gesture APIs?** (`Gesture.Pan`, `Gesture.Pinch`, `Gesture.Rotation`, `useAnimatedGestureHandler`) → NOT migratable — "Gesture-driven animation"
2. **Uses scroll handler?** (`useAnimatedScrollHandler`, `onScroll` with `Animated.event`) → NOT migratable — "Scroll-driven animation"
3. **Uses shared element transitions?** (`sharedTransitionTag`) → NOT migratable — "Shared element transition"
4. **Uses `runOnUI` or worklet directives?** → NOT migratable — "Requires worklet runtime"
5. **Uses `withSequence`?** → NOT migratable — "Animation sequencing not supported"
5b. **Uses `withDelay` wrapping a single animation (`withTiming`/`withSpring`)?** → MIGRATABLE — map to `delay` on the transition
5c. **Uses `withDelay` wrapping `withSequence` or nested `withDelay`?** → NOT migratable — "Complex delay/sequencing not supported"
6. **Uses complex `interpolate()`?** (more than 2 input/output values) → NOT migratable — "Complex interpolation"
7. **Uses `layout={...}` prop?** → NOT migratable — "Layout animation"
8. **Animates unsupported properties?** (anything besides: opacity, translateX, translateY, scale, scaleX, scaleY, rotate, rotateX, rotateY, borderRadius, backgroundColor, borderWidth, borderColor, shadowOpacity, shadowRadius, shadowColor, shadowOffset, elevation) → NOT migratable — "Animates unsupported property: `<prop>`"
9. **Uses different transition configs per property?** (e.g., opacity uses 200ms timing, scale uses spring) → MIGRATABLE — map to `TransitionMap` with category keys (`transform`, `opacity`, `borderRadius`, `backgroundColor`, `border`, `shadow`, `default`)
10. **Not driven by state?** (animation triggered by gesture/scroll value, not React state) → NOT migratable — "Not state-driven"
11. **Otherwise** → MIGRATABLE
### Migratable Pattern Mapping
Use this table to convert Reanimated/Animated patterns to EaseView:
| Reanimated / Animated Pattern | EaseView Equivalent |
| ------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ |
| `useSharedValue` + `useAnimatedStyle` + `withTiming` for opacity, translate, scale, rotate, borderRadius, backgroundColor | `animate={{ prop: value }}` + `transition={{ type: 'timing', duration, easing }}` |
| `withSpring` | `transition={{ type: 'spring', damping, stiffness, mass }}` |
| `entering={FadeIn}` / `FadeIn.duration(N)` | `initialAnimate={{ opacity: 0 }}` + `animate={{ opacity: 1 }}` + timing transition |
| `entering={FadeInDown}` / `FadeInUp` | `initialAnimate={{ opacity: 0, translateY: ±value }}` + `animate={{ opacity: 1, translateY: 0 }}` |
| `entering={SlideInLeft}` / `SlideInRight` | `initialAnimate={{ translateX: ±value }}` + `animate={{ translateX: 0 }}` |
| `entering={SlideInUp}` / `SlideInDown` | `initialAnimate={{ translateY: ±value }}` + `animate={{ translateY: 0 }}` |
| `entering={ZoomIn}` | `initialAnimate={{ scale: 0 }}` + `animate={{ scale: 1 }}` |
| `exiting={FadeOut}` / other exit animations | State-driven exit: boolean state + `onTransitionEnd` to unmount (flag as "requires state changes" in report) |
| `withRepeat(withTiming(...), -1, false)` | `transition={{ type: 'timing', ..., loop: 'repeat' }}` + `initialAnimate` for start value |
| `withRepeat(withTiming(...), -1, true)` | `transition={{ type: 'timing', ..., loop: 'reverse' }}` + `initialAnimate` for start value |
| `Easing.linear` | `easing: 'linear'` |
| `Easing.ease` / `Easing.inOut(Easing.ease)` | `easing: 'easeInOut'` |
| `Easing.in(Easing.ease)` | `easing: 'easeIn'` |
| `Easing.out(Easing.ease)` | `easing: 'easeOut'` |
| `Easing.bezier(x1, y1, x2, y2)` | `easing: [x1, y1, x2, y2]` |
| `Animated.Value` + `Animated.timing` | Same `animate` + `transition` pattern — convert to state-driven |
| `Animated.Value` + `Animated.spring` | `animate` + `transition={{ type: 'spring' }}` — convert to state-driven |
| `withDelay(ms, withTiming(...))` or `withDelay(ms, withSpring(...))` | `transition={{ ..., delay: ms }}` — add `delay` to the transition config |
| `entering={FadeIn.delay(ms)}` / any entering preset with `.delay()` | `initialAnimate` + `animate` + `transition={{ ..., delay: ms }}` |
| Different `withTiming`/`withSpring` per property in `useAnimatedStyle` | `transition={{ opacity: { type: 'timing', ... }, transform: { type: 'spring', ... } }}` (per-property map) |
### Default Value Mapping
**CRITICAL: Reanimated and EaseView have different defaults. You MUST explicitly set values to preserve the original animation behavior. Do not rely on EaseView defaults matching Reanimated defaults.**
**Use `reanimatedVersion` from Phase 1 to select the correct defaults.**
#### `withSpring` → EaseView spring
**Reanimated v2/v3 defaults:**
| Parameter | Reanimated v2/v3 | EaseView default | Action |
|---|---|---|---|
| `damping` | `10` | `15` | **Must set `damping: 10`** |
| `stiffness` | `100` | `120` | **Must set `stiffness: 100`** |
| `mass` | `1` | `1` | Same — omit |
**Reanimated v4 defaults:**
| Parameter | Reanimated v4 | EaseView default | Action |
|---|---|---|---|
| `damping` | `120` | `15` | **Must set `damping: 120`** |
| `stiffness` | `900` | `120` | **Must set `stiffness: 900`** |
| `mass` | `4` | `1` | **Must set `mass: 4`** |
Reanimated v4 changed to a critically damped, snappy spring (no bounce) as the default. The rationale was that the old physics-based defaults were too sensitive to start/end conditions. v4 recommends using `duration` + `dampingRatio` instead of raw physics params.
If the source code explicitly sets any of these values, carry them over as-is. If the source relies on Reanimated defaults (no explicit value), set the Reanimated default explicitly on the EaseView transition.
Example — bare `withSpring(1)` with no config:
```typescript
// Before (Reanimated)
scale.value = withSpring(1);
// After (EaseView) — v2/v3: set damping: 10, stiffness: 100
transition={{ type: 'spring', damping: 10, stiffness: 100 }}
// After (EaseView) — v4: set damping: 120, stiffness: 900, mass: 4
transition={{ type: 'spring', damping: 120, stiffness: 900, mass: 4 }}
```
**Duration-based spring:** Reanimated v3+ also supports `withSpring(target, { duration, dampingRatio })`. If the code explicitly sets `dampingRatio`/`duration`, convert using: `damping = dampingRatio * 2 * sqrt(stiffness * mass)`.
#### `withTiming` → EaseView timing
| Parameter | Reanimated default | EaseView default | Action |
|---|---|---|---|
| `duration` | `300` | `300` | Same — omit |
| `easing` | `Easing.inOut(Easing.quad)` | `'easeInOut'` (cubic) | **Must set `easing: [0.455, 0.03, 0.515, 0.955]`** |
The easing curves are different! Reanimated's default is quadratic ease-in-out, EaseView's is cubic. Always set the easing explicitly when the source doesn't specify one.
Example — bare `withTiming(1)` with no config:
```typescript
// Before (Reanimated)
opacity.value = withTiming(1);
// After (EaseView) — must set quad easing to match
transition={{ type: 'timing', duration: 300, easing: [0.455, 0.03, 0.515, 0.955] }}
```
If the source explicitly sets an easing, map it using the easing table above.
#### `Animated.timing` (old RN API) → EaseView timing
| Parameter | RN Animated default | EaseView default | Action |
|---|---|---|---|
| `duration` | `500` | `300` | **Must set `duration: 500`** |
| `easing` | `Easing.inOut(Easing.ease)` | `'easeInOut'` | Same curve — omit |
#### `Animated.spring` (old RN API) → EaseView spring
RN Animated uses `friction`/`tension` by default: `friction: 7, tension: 40`. These map to: `stiffness = tension`, `damping = friction`.
| Parameter | RN Animated default | EaseView default | Action |
|---|---|---|---|
| stiffness (tension) | `40` | `120` | **Must set `stiffness: 40`** |
| damping (friction) | `7` | `15` | **Must set `damping: 7`** |
| mass | `1` | `1` | Same — omit |
### Unit Conversions
- **Rotation:** Reanimated uses `'45deg'` strings in transforms → EaseView uses `45` (number, degrees). Strip the `'deg'` suffix and parse to number.
- **Translation:** Both use DIPs (density-independent pixels). No conversion needed.
- **Scale:** Both use unitless multipliers. No conversion needed.
---
## Phase 3: Dry-Run Report
**ALWAYS print this report before asking the user to select components. This report must be visible to the user before Phase 4.**
Print a structured report. Do NOT apply any changes yet.
Format:
```
## Migration Report
### Summary
- Files scanned: X
- Components with animations: Y
- Migratable: Z | Not migratable: W
### Migratable Components
#### `path/to/file.tsx` — ComponentName
**Current:** Brief description of what the animation does and which API it uses
**Proposed:** What the EaseView equivalent looks like (include exact transition values with mapped defaults)
**Changes:** What will be added/removed/modified
**Note:** (only if applicable) "Requires state changes for exit animation" or other caveats
### Not Migratable (will be skipped)
#### `path/to/file.tsx` — ComponentName
**Reason:** Why it can't be migrated (from decision tree)
```
This report MUST be printed as text output in the conversation — not inside a plan, not collapsed. The user needs to read it before selecting components in Phase 4.
---
## Phase 4: User Confirmation
**CRITICAL: You MUST use the `AskUserQuestion` tool here. Do NOT use plan mode, do NOT use text prompts, do NOT ask inline. Call the `AskUserQuestion` tool directly.**
Call `AskUserQuestion` with these exact parameters:
- `multiSelect`: `true`
- `questions`: a single question object with:
- `header`: `"Migrate"`
- `question`: `"Which components should be migrated to EaseView? All are selected — deselect any to skip."`
- `multiSelect`: `true`
- `options`: one entry per migratable component, each with:
- `label`: the component name (e.g., `"AnimatedButton"`)
- `description`: file path and brief animation description (e.g., `"src/components/animated-button.tsx — spring scale on press"`)
Example tool call for 2 migratable components:
```json
{
"questions": [
{
"header": "Migrate",
"question": "Which components should be migrated to EaseView? All are selected — deselect any to skip.",
"multiSelect": true,
"options": [
{
"label": "AnimatedButton",
"description": "src/components/simple/animated-button.tsx — spring scale on press"
},
{
"label": "Collapsible",
"description": "src/components/ui/collapsible.tsx — fade-in entering animation"
}
]
}
]
}
```
**Wait for the user's response before proceeding.** Do not enter plan mode. Do not apply any changes without the user selecting components.
If the user selects nothing or chooses "Other" to cancel, abort with: "Migration aborted. No changes were made."
Only proceed to Phase 5 with the components the user confirmed.
---
## Phase 5: Apply Migrations
For each confirmed component, apply the migration:
### Migration Steps (per component)
1. **Add EaseView import** if not already present:
```typescript
import { EaseView } from 'react-native-ease';
```
1b. **If `usesNativeWind` is true**, check if `import 'react-native-ease/nativewind'` already exists in the project (search all files). If not, add it to the app's root entry point (e.g., `_layout.tsx`, `App.tsx`, or `index.tsx` — whichever is the earliest entry). This only needs to be done once across all migrations, not per component.
2. **Replace the animated view:**
- `Animated.View` → `EaseView`
- `<Animated.View style={[styles.box, animatedStyle]}>` → `<EaseView style={styles.box} animate={{ ... }} transition={{ ... }}>`
3. **Convert animation hooks to props:**
- Remove `useSharedValue`, `useAnimatedStyle`, `withTiming`, `withSpring`, `withRepeat` calls
- Convert their values into `animate`, `initialAnimate`, and `transition` props
4. **Convert entering/exiting animations:**
- `entering={FadeIn}` → `initialAnimate={{ opacity: 0 }}` on the EaseView + `animate={{ opacity: 1 }}`
- For `exiting`: introduce a state variable and `onTransitionEnd` callback:
```typescript
const [visible, setVisible] = useState(true);
const [mounted, setMounted] = useState(true);
// When triggering exit:
setVisible(false);
// On the EaseView:
{
mounted && (
<EaseView
animate={{ opacity: visible ? 1 : 0 }}
transition={{ type: 'timing', duration: 300 }}
onTransitionEnd={({ finished }) => {
if (finished && !visible) setMounted(false);
}}
>
...
</EaseView>
);
}
```
5. **Clean up imports:**
- Remove Reanimated imports that are no longer used in the file
- Keep any Reanimated imports still referenced by non-migrated code in the same file
- Never remove imports that are still used
6. **Print progress:**
```
[1/N] Migrated ComponentName in path/to/file.tsx
```
### Safety Rules
These rules are non-negotiable. Violating them corrupts user code.
1. **When in doubt, skip.** If a pattern is ambiguous or you're not confident in the migration, add it to "Not Migratable" with reason: "Complex pattern — manual review recommended"
2. **Never remove imports still used elsewhere in the file.** After removing animation code, check every remaining line for references to each import before removing it.
3. **Preserve all non-animation logic.** Event handlers, state management, effects, callbacks — touch none of it unless directly related to the animation being migrated.
4. **Preserve component structure and public API.** Props, ref forwarding, exported types — keep them identical.
5. **Handle mixed files correctly.** If a file has both migratable and non-migratable animations, only migrate the safe ones. Keep Reanimated imports if any Reanimated code remains.
6. **Map rotation units correctly.** Reanimated `'45deg'` string → EaseView `45` number. If the source uses radians, convert: `radians * (180 / Math.PI)`.
7. **Map easing presets correctly.** See the mapping table in Phase 2.
8. **Do not introduce TypeScript errors.** Ensure all types are correct after migration. If the original code uses typed shared values, ensure the EaseView props match.
---
## Phase 6: Final Report
After all migrations are applied, print:
```
## Migration Complete
### Changed (X components)
- `path/to/file.tsx` — ComponentName: brief description of what was migrated
### Unchanged (Y components)
- `path/to/file.tsx` — ComponentName: reason skipped
### Next Steps
- Run your app and verify animations visually
- Run your test suite to check for regressions
- If no Reanimated code remains, consider removing `react-native-reanimated` from dependencies
```
---
## EaseView API Reference (for migration accuracy)
### Supported Animatable Properties
All properties in the `animate` prop:
| Property | Type | Default | Notes |
| ----------------- | ------------ | --------------- | ------------------------------------ |
| `opacity` | `number` | `1` | 0–1 range |
| `translateX` | `number` | `0` | In DIPs (density-independent pixels) |
| `translateY` | `number` | `0` | In DIPs |
| `scale` | `number` | `1` | Shorthand for scaleX + scaleY |
| `scaleX` | `number` | `1` | Overrides scale for X axis |
| `scaleY` | `number` | `1` | Overrides scale for Y axis |
| `rotate` | `number` | `0` | Z-axis rotation in degrees |
| `rotateX` | `number` | `0` | X-axis rotation in degrees (3D) |
| `rotateY` | `number` | `0` | Y-axis rotation in degrees (3D) |
| `borderRadius` | `number` | `0` | In pixels |
| `backgroundColor` | `ColorValue` | `'transparent'` | Any RN color value |
| `borderWidth` | `number` | `0` | In pixels |
| `borderColor` | `ColorValue` | `'black'` | Any RN color value |
| `shadowOpacity` | `number` | `0` | 0–1 (iOS only) |
| `shadowRadius` | `number` | `0` | In pixels (iOS only) |
| `shadowColor` | `ColorValue` | `'black'` | Any RN color value (iOS only) |
| `shadowOffset` | `object` | `{width:0,height:0}` | `{ width, height }` (iOS only) |
| `elevation` | `number` | `0` | Android material shadow |
### Transition Types
**Timing:**
```typescript
transition={{
type: 'timing',
duration: 300, // ms, default 300
easing: 'easeInOut', // 'linear' | 'easeIn' | 'easeOut' | 'easeInOut' | [x1,y1,x2,y2]
delay: 0, // ms, default 0
loop: 'repeat', // 'repeat' | 'reverse' — requires initialAnimate
}}
```
**Spring:**
```typescript
transition={{
type: 'spring',
damping: 15, // default 15
stiffness: 120, // default 120
mass: 1, // default 1
delay: 0, // ms, default 0
}}
```
**None (instant):**
```typescript
transition={{ type: 'none' }}
```
### Key Props
- `animate` — target values for animated properties
- `initialAnimate` — starting values (animates to `animate` on mount)
- `transition` — animation config: a single `SingleTransition` (timing/spring/none) OR a `TransitionMap` with category keys (`default`, `transform`, `opacity`, `borderRadius`, `backgroundColor`, `border`, `shadow`)
- `onTransitionEnd` — callback with `{ finished: boolean }`
- `transformOrigin` — pivot point as `{ x: 0-1, y: 0-1 }`, default center
- `useHardwareLayer` — Android GPU optimization (boolean, default false)
- `className` — NativeWind / Tailwind CSS class string (requires NativeWind in the project)
### Important Constraints
- **Loop requires timing** (not spring) and `initialAnimate` must define the start value
- **Per-property transitions supported** — pass a `TransitionMap` with category keys (`default`, `transform`, `opacity`, `borderRadius`, `backgroundColor`, `border`, `shadow`) to use different configs per property group
- **No animation sequencing** — no equivalent to `withSequence`. Simple `withDelay` IS supported via the `delay` transition prop
- **No gesture/scroll-driven animations** — EaseView is state-driven only
- **Style/animate conflict** — if a property appears in both `style` and `animate`, the animated value wins
Creator's repository · appandflow/react-native-ease