Hash Index
An index structure that uses a hash function to map keys to bucket locations. Provides O(1) lookup for equality queries but does not support range queries.
Hash Indexes: O(1) Point Lookups
Mapping a key to a fixed-size bucket so point lookups skip the scan entirely.
Hash Indexes in Production: Partitioned Tables and Hashing Schemes
Hash-partitioned tables, consistent hashing on disk, and open addressing.
Advanced Hash Index: DynamoDB-Style and Hash-Range Keys
Composite hash-range keys, hot-key mitigation, and hash index internals under load.
Hash Indexes: Review & Mastery Quiz
Scenario questions on structure, partitioning, and hot keys.
Free Books & Guides
Refactoring.Guru — Hash Index
The definitive modern guide to the Hash Index pattern. Clear explanations, UML diagrams, real-world analogies, and code examples in multiple languages.
SourceMaking — Hash Index
A comprehensive companion guide covering the Hash Index pattern with detailed rules of thumb, criticisms, and robust code snippets.
GoF Design Patterns — Hash Index
The original Gang of Four book describing the pattern. Available in the "Design Patterns: Elements of Reusable Object-Oriented Software" on Wikipedia.
Official Documentation
Video Courses
freeCodeCamp — Design Patterns Course
A comprehensive multi-hour video course covering all major design patterns with implementations in JavaScript and TypeScript.
Design Patterns in Modern JavaScript Playlist
YouTube playlist covering creational, structural, and behavioral patterns with clear code walkthroughs.
Web Dev Simplified — Hash Index
Clear, concise video tutorials covering design patterns with practical examples.
Practice & Examples
Awesome Low-Level Design (GitHub)
A curated collection of free LLD resources, pattern implementations, and interview problems across multiple languages.
Design Patterns Implementation (GitHub)
The most popular open-source collection of design pattern implementations with detailed explanations.
Refactoring.Guru Examples in Hash Index
Code examples of the Hash Index pattern in TypeScript, Python, Java, and more.