mixpanel-react-native/claude/updates/pattern-evolution-2025-05-30.md

Official React Native Tracking Library for Mixpanel Analytics

# Pattern Evolution Analysis - 2025-05-30

## Evolved Patterns

### 1. UUID Generation Pattern Evolution

**Pattern Lifecycle Stage**: 🌿 Growing

**Previously Documented**:
```javascript
this._identity[token].deviceId = uuid.v4();
```

**Evolved Pattern**:
```javascript
try {
  this._identity[token].deviceId = randomUUID();
} catch (e) {
  this._identity[token].deviceId = uuid.v4();
}
```

**Evolution Notes**:
- Adopted try-catch pattern for Expo compatibility
- Prefers expo-crypto's randomUUID() when available
- Gracefully falls back to uuid.v4() for non-Expo environments
- Pattern is in "Growing" stage - new code uses this approach

### 2. Storage Instance Initialization

**Pattern Lifecycle Stage**: 🌳 Mature

**Previously Documented**:
```javascript
MixpanelPersistent.getInstance(storage);
```

**Evolved Pattern**:
```javascript
MixpanelPersistent.getInstance(storage, token);
```

**Evolution Context**:
- Improved token-scoped initialization
- Better isolation between multiple Mixpanel instances
- Ensures proper initialization completion per token

### 3. Conditional Property Inclusion

**Pattern Lifecycle Stage**: 🌱 Emerging

**New Pattern**:
```javascript
const profileData = {
  $token: token,
  $time: Date.now(),
  ...action,
  ...(distinctId != null && { $distinct_id: distinctId }),
  ...(deviceId != null && { $device_id: deviceId }),
  ...(userId != null && { $user_id: userId }),
};
```

**Pattern Context**:
- Prevents sending null/undefined values to API
- Uses modern JavaScript conditional spread syntax
- Cleaner than previous approach of always including properties

### 4. Queue Identity Management

**Pattern Lifecycle Stage**: 🌿 Growing

**New Addition**:
```javascript
await this.core.identifyUserQueue(token);
```

**Pattern Context**:
- Ensures user queue is properly updated after identification
- Addresses issue where engage events were sent before identification
- Part of improved identity management flow

### 5. Storage Module Resolution

**Pattern Lifecycle Stage**: 🌳 Mature

**Enhanced Pattern**:
```javascript
const storageModule = require("@react-native-async-storage/async-storage");
if (storageModule.default) {
  this.storage = storageModule.default
} else {
  this.storage = storageModule
}
```

**Evolution Notes**:
- Handles both ES6 default exports and CommonJS exports
- More robust module resolution
- Prevents issues with different bundler configurations

## New Helper Methods

### Identity Check Helper
```javascript
isIdentified(token) {
  return Boolean(this.getUserId(token));
}
```

**Pattern**: Convenience method for common checks
**Follows**: Existing helper method patterns in codebase

## Configuration Pattern Extension

### Gzip Compression Support
Added throughout the stack as optional configuration:
- API level: `init(..., useGzipCompression = false)`
- Native iOS: Additional parameter in initialize
- Native Android: Additional parameter handling
- Maintains backward compatibility with default false

## Import Formatting Evolution

**Previous**: Inconsistent spacing
**Current**: Consistent destructuring imports with spaces
```javascript
import { MixpanelCore } from "./mixpanel-core";
```

This appears to be from automated formatting (prettier/eslint), indicating improved code quality tooling.