Molniya

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Examples ​

Real-world examples demonstrating Molniya in practical scenarios.

Overview ​

These examples show complete, runnable solutions to common data processing problems. Each example includes:

  • Sample data setup
  • Step-by-step transformation
  • Explanation of key concepts
  • Expected output

Available Examples ​

Sales Analysis ​

Analyze sales data to find top products, revenue trends, and customer behavior.

Covers:

  • Reading CSV data
  • Filtering and grouping
  • Calculating aggregations
  • Time-based analysis

Log Processing ​

Parse and analyze web server logs to find popular endpoints, error rates, and response times.

Covers:

  • String parsing
  • Pattern matching
  • High-volume filtering
  • Statistical summaries

ETL Pipeline ​

Extract, transform, and load data between different formats and systems.

Covers:

  • Multiple data sources
  • Data cleaning
  • Type conversions
  • Output formatting

Data Cleaning ​

Clean messy real-world data: handle nulls, fix types, remove duplicates.

Covers:

  • Null handling
  • Type casting
  • Deduplication
  • Validation

Running the Examples ​

All examples assume you have Molniya installed:

bash
bun add molniya

And use this import pattern:

typescript
import { 
  readCsv, fromRecords, col, lit, and, or,
  sum, avg, min, max, count, asc, desc,
  DType, unwrap, createSchema
} from "molniya";

Sample Data ​

Many examples use inline CSV strings for reproducibility:

typescript
const csvData = `
id,name,category,price,quantity
1,Laptop,Electronics,999.99,5
2,Mouse,Electronics,29.99,50
3,Desk,Furniture,299.99,10
`.trim();

const df = fromCsvString(csvData, {
  id: DType.int32,
  name: DType.string,
  category: DType.string,
  price: DType.float64,
  quantity: DType.int32
});

Performance Notes ​

Examples are written for clarity. For production use with large datasets:

  1. Filter early - Apply filters before expensive operations
  2. Select only needed columns - Reduces memory usage
  3. Use streaming - readCsv() streams by default
  4. Limit during development - Use .limit(1000) while testing

Next Steps ​