🔢 How do you combine or manipulate data in your projects?

[Hangell]

Combinare is a TypeScript library focused on combinatorics, permutations, and functional utilities for data manipulation.

I’d love to hear from you:

What are the most common cases where you need to combine arrays, sets, or objects?

Do you often need utilities for permutations, combinations, or functional patterns?

Are there features you wish existed in existing libraries (like Lodash, Ramda, etc.) that Combinare could bring in a lightweight way?

Feel free to share use cases, feature requests, or even “dream utilities” that would make your daily development easier. 🚀

[DanieleRangel]

Combinare Library - Use Cases and Feature Suggestions

Common Use Cases I Encounter

Data Analysis & Testing

• A/B Testing Scenarios - Combining different UI components, copy variations, and user segments to generate test permutations
• Configuration Testing - Generating all possible combinations of feature flags, environment settings, and user permissions
• Dataset Cross-Analysis - Combining multiple data sources to find correlations and patterns

E-commerce & Product Management

• Product Variant Generation - Combining attributes like size, color, material to create product SKUs
• Bundle Recommendations - Creating product bundles by combining complementary items
• Pricing Strategy Testing - Permuting different pricing models across product categories

Game Development & Simulations

• Character/Item Generation - Combining traits, abilities, and equipment for procedural content
• Scenario Planning - Generating different game states by combining player actions and environmental factors

API & Data Processing

• Query Parameter Combinations - Testing different API endpoint configurations
• Database Query Optimization - Generating different join combinations and indexing strategies
• Form Validation Testing - Creating all possible input combinations for comprehensive testing

Features Missing from Existing Libraries

Performance-Focused Combinatorics

// Dream utility: Lazy evaluation for large sets
combinare.lazy([1,2,3,4,5]).combinations(3).take(100); // Only compute first 100
combinare.stream(largeDataset).permutations().filter(condition).collect();

Constraint-Based Generation

// Generate combinations with business rules
combinare.constrained(products)
  .combinations(3)
  .where(bundle => bundle.totalPrice < 100)
  .where(bundle => bundle.categories.size >= 2);

Functional Pipeline Integration

// Seamless chaining with functional operations
combinare(users)
  .cartesianProduct(roles, departments)
  .map(([user, role, dept]) => ({ ...user, role, dept }))
  .filter(assignment => isValidAssignment(assignment))
  .groupBy(assignment => assignment.dept);

Type-Safe Operations (TypeScript)

// Compile-time safety for combination operations
interface Product { id: string; category: 'A' | 'B' | 'C' }
combinare<Product>(products)
  .combinations(2)
  .ensure<{ differentCategories: boolean }>(); // Type-guided constraints

"Dream Utilities" That Would Be Game-Changers

Smart Deduplication

// Intelligent duplicate removal based on custom equality
combinare.dedupe(combinations, (a, b) => deepEqual(a.sort(), b.sort()));

Memory-Efficient Streaming

// Handle massive datasets without memory issues
combinare.fromStream(dataStream)
  .combinations(4)
  .toAsyncIterable(); // Process combinations as they're generated

Probability-Weighted Generation

// Generate combinations based on likelihood/weights
combinare.weighted(items, weights).combinations(3).sample(1000);

Incremental Combination Building

// Build combinations step by step with validation at each step
combinare.builder()
  .add(item => isValidFirst(item))
  .then(item => isValidSecond(item))
  .build();

Mathematical Operations on Combination Sets

// Set operations on combination results
const setA = combinare(dataA).combinations(2);
const setB = combinare(dataB).combinations(2);

combinare.union(setA, setB);
combinare.intersection(setA, setB);
combinare.difference(setA, setB);

Integration Wish List

Framework Integrations

• React Hooks - useCombinations, usePermutations for UI state management
• Vue Composables - Similar reactive utilities for Vue 3
• RxJS Integration - Observable streams of combinations

Performance Optimizations

• Worker Thread Support - Offload heavy computations to prevent UI blocking
• WebAssembly Module - Ultra-fast core operations for large datasets
• Caching Layer - Intelligent memoization for repeated operations

Validation & Schema Integration

• Joi/Yup/Zod Integration - Work with popular validation libraries for constraint validation
• JSON Schema Support - Generate combinations based on schema definitions

Export & Interoperability

• Multiple Output Formats - Direct export to CSV, JSON, XML
• Database Integration - Direct write to SQL databases or NoSQL stores
• Streaming APIs - Integration with Node.js streams

Specific Pain Points Combinare Could Solve

1. Memory Limitations

Current libraries often generate all combinations in memory, causing issues with large datasets. Need lazy evaluation and streaming support.

2. Business Logic Integration

Most libraries are purely mathematical. Need constraint-based generation that integrates with business rules and validation logic.

3. Performance at Scale

When dealing with thousands of items, current solutions become unusable. Need parallel processing and incremental generation.

4. Type Safety

JavaScript/TypeScript developers need compile-time guarantees about combination structure and constraints.

5. Real-World Workflows

Current libraries don't integrate well with modern development workflows. Need framework integration, testing utilities, and debugging tools.

Conclusion

The key gap I see is that most libraries are either too basic (simple array operations) or too academic (pure math focus). Combinare could bridge this by being developer-friendly while mathematically robust - perfect for real-world applications where you need both power and practicality.

The sweet spot would be a library that:

• ✅ Handles large datasets efficiently
• ✅ Integrates with modern JavaScript ecosystems
• ✅ Provides type safety and developer experience
• ✅ Supports complex business logic and constraints
• ✅ Offers both simple APIs for basic use cases and advanced features for complex scenarios