optimized-diff

@adobe/optimized-diff

High-performance deep object diff algorithm with significant performance improvements over generic libraries.

Overview

@adobe/optimized-diff provides 60-80% performance improvements over generic diff libraries like deep-object-diff while maintaining full API compatibility. It's optimized for comparing complex JavaScript objects with nested structures and large datasets.

Features

• 🚀 High Performance: 2-3x faster than generic diff libraries
• 🎯 Deep Object Optimized: Designed for complex nested object structures
• 📦 Drop-in Replacement: Compatible with deep-object-diff API
• 🔍 Zero Dependencies: No external runtime dependencies
• 📏 Linear Scaling: O(n) complexity with predictable performance
• 💾 Memory Efficient: No unnecessary object cloning or sanitization

Performance

Benchmarked against real-world structured data (2,282 objects):

Original (deep-object-diff): 37.40ms average
Optimized implementation:     13.57ms average
Improvement: 63.7% faster (2.8x speedup)

Installation

Within the Spectrum Tokens monorepo:

pnpm add @adobe/optimized-diff

API

Basic Usage

import {
  detailedDiff,
  diff,
  addedDiff,
  deletedDiff,
  updatedDiff,
} from "@adobe/optimized-diff";

const original = {
  user: {
    name: "John Doe",
    preferences: {
      theme: "dark",
      notifications: true,
    },
    tags: ["admin", "user"],
  },
  settings: {
    language: "en",
  },
};

const updated = {
  user: {
    name: "John Smith", // changed
    preferences: {
      theme: "light", // changed
      notifications: true,
      timezone: "UTC", // added
    },
    tags: ["admin", "user", "premium"], // changed
  },
  settings: {
    language: "en",
  },
  metadata: {
    // added
    lastLogin: "2024-01-15",
  },
};

// Get detailed diff with categorized changes
const result = detailedDiff(original, updated);
console.log(result);
// {
//   added: {
//     user: { preferences: { timezone: "UTC" } },
//     metadata: { lastLogin: "2024-01-15" }
//   },
//   updated: {
//     user: {
//       name: "John Smith",
//       preferences: { theme: "light" },
//       tags: ["admin", "user", "premium"]
//     }
//   },
//   deleted: {}
// }

Available Functions

// Detailed diff with categorized results
const detailed = detailedDiff(original, updated);

// Combined diff (all changes in one object)
const combined = diff(original, updated);

// Only added properties
const added = addedDiff(original, updated);

// Only deleted properties
const deleted = deletedDiff(original, updated);

// Only updated properties
const updated = updatedDiff(original, updated);

Engine Object

import OptimizedDiffEngine from "@adobe/optimized-diff";

// Access all methods through the engine
const result = OptimizedDiffEngine.detailedDiff(original, updated);

// Engine metadata
console.log(OptimizedDiffEngine.name); // "optimized"
console.log(OptimizedDiffEngine.version); // "1.0.0"
console.log(OptimizedDiffEngine.description); // "High-performance diff..."

Algorithm Details

The optimization provides performance improvements through:

1. Set-based Key Lookups: O(1) key existence checks instead of O(n) iterations
2. Early Reference Checking: Skip expensive deep comparison for identical object references
3. Structure-aware Logic: Optimized for common nested object patterns and structures
4. Efficient Memory Usage: No unnecessary object cloning or sanitization steps

Benchmarking

Run the included benchmark to test performance on your system:

cd tools/optimized-diff
pnpm run benchmark

Or use moon:

moon run optimized-diff:benchmark

Sample benchmark output:

📊 Testing with 1000 objects:
   Dataset: 1000 objects, 300 changes (30.0%)

   ⚡ Optimized Diff:
      Average: 8.23ms
      Range: 7.85ms - 8.92ms

   📈 deep-object-diff:
      Average: 24.67ms
      Range: 23.11ms - 26.43ms

   🎯 Performance Improvement:
      66.6% faster (3.0x speedup)
      Time saved: 16.44ms per operation

Testing

Run the test suite:

cd tools/optimized-diff
pnpm test

Or use moon:

moon run optimized-diff:test

Technical Details

Compatibility

Fully compatible with deep-object-diff API:

• Same function signatures
• Same return value structures
• Same edge case handling
• Same array processing (as objects with numeric keys)

Limitations

• Optimized for object-heavy workloads (structured data, configurations)
• Not optimized for deeply nested arrays or complex circular references
• Focuses on common nested object patterns rather than extremely dynamic structures

When to Use

Best for:

• Large structured object comparisons
• Configuration file diffing
• JSON data comparisons
• Performance-critical diff operations
• Nested data with consistent patterns

Consider alternatives for:

• Simple object comparisons (overhead not worth it)
• Highly dynamic object structures
• Complex circular reference handling

Integration Examples

With Data Comparison Tools

import { detailedDiff } from "@adobe/optimized-diff";

// Replace generic diff libraries
function compareData(original, updated) {
  const changes = detailedDiff(original, updated);
  // ... rest of comparison logic
}

Migration from deep-object-diff

// Before
import { detailedDiff } from "deep-object-diff";

// After
import { detailedDiff } from "@adobe/optimized-diff";

// API is identical - no code changes needed!

License

Apache-2.0

Contributing

This package is part of the Spectrum Tokens monorepo. See the main repository for contribution guidelines.