JavaScript Architecture: Design Patterns & SOLID Principles

Explore solid principles for clean JavaScript code, focusing on the single responsibility principle, open-closed principle, Liskov substitution principle, interface segregation principle, and dependency inversion principle.

Following solid principles provides a strong foundation for maintainable, change-ready code, enabling easy component swaps, saving time, and delivering reliable, user-friendly software.

The single responsibility principle limits the impact of changes by giving a class one reason to change, and guides refactoring into dedicated classes like a user validator and notification manager.

Explore the open/closed principle by designing extensible, bug free code in JavaScript, using a discount strategy interface and composition to extend behavior without modifying the order class.

Explain the Liskov substitution principle as subtypes must replace base types without breaking the program, using a bird example and a flyable interface to ensure substitutability and maintainable design.

Learn how to implement a task builder using the builder pattern in JavaScript, with chainable setName, setDescription, setDueDate, and a final build method.

Build mazes with an abstract maze builder and concrete builders, detailing standard and trap mazes, rooms, walls, doors, and directions to showcase extensibility.

Explore the builder pattern's consequences by providing abstract interface for constructing a product, hiding assembly details, and enabling changes to the internal representation with a new builder under director control.

Explore how the maze game models a map site with rooms, walls, and doors using the abstract factory pattern, where each room has a number and an enter method.

Create a playable maze game by constructing rooms, walls, and doors, managing the current room, and using try direction and open actions to move between rooms.

Guarantee a single, accessible instance to manage shared resources with lazy initialization, improving startup time and memory usage, while enabling mocks in testing and maintaining consistent state and thread safety.

Explore the singleton design pattern use cases, showing how a single instance and global access keep logs, database connections, settings, and caches consistent and fast.

Explore the singleton pattern in JavaScript by implementing a printer with a static getInstance and a function-based approach, tracking run numbers and on/off state.

The single item pattern, or singleton, provides controlled access to the sole instance, reduces namespace pollution, supports subclassing for runtime configuration, and lets you vary the number of instances.

Explore how to implement the prototype pattern in JavaScript to create and clone music note objects with a base note, duration, and graphic, improving efficiency.

Examine the prototype pattern's consequences in JavaScript, showing how prototypes can be registered with a prototype manager to add or remove products at runtime and clone objects.

Explore how the adapter pattern transforms interfaces to enable communication between incompatible components, promoting compatibility and flexibility while noting added complexity and overuse risks.

Explore the adapter pattern by bridging an old calculator interface with a refactored, more efficient new version, while honoring the open-closed principle and maintaining backward compatibility.

Explore how to implement an MMORPG game in JavaScript using bridge and chaining patterns, with a living thing abstraction, characters, body parts, and HP-based combat.

Explore the bridge pattern in JavaScript: split variants into separate class hierarchies to improve maintainability, switch implementations at runtime, and apply the open class and single responsibility principles.

Explore the composite design pattern through a tree analogy, showing treatment of individual and composite objects within part-whole hierarchies, with benefits, drawbacks, and use cases like GUIs and file systems.

Explore the decorator pattern, extending a basic object at runtime by applying decorators without altering its structure, enabling dynamic responsibilities and flexible functionality across gui toolkits, i/o streams, and middleware.

Explore the email decorator pattern by building a general mail class and layered decorators—encrypt, voice, and sign—to compose flexible, testable email pipelines in JavaScript.