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Understanding JavaScript Design Patterns In Depth

By Kitakabee, Community Contributor -

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JavaScript (JS) is a lightweight, interpretive, object-oriented programming language with first-class functions widely used as web page scripting. Design patterns are reusable code that is applied to solving commonly occurring problems.

Design patterns combine the expertise of several developers to organize the code efficiently, addressing the issues a person is trying to solve. They also provide a common language for discussing the problems.

This article explains the top five JavaScript design patterns, most of which naturally fit into one of three categories: Design themes, Structural engineering patterns, and Behavioural design patterns.

Benefits of JavaScript Design Patterns

Listed below are some of the benefits of Javascript design patterns:

  • Expressive: Design patterns may elegantly describe a huge solution.
  • Eliminate the Requirement for Code Refactoring: When an application is created using design patterns in consideration, you may not need to rewrite the code later since applying the relevant design pattern to a particular problem is usually an effective solution.
  • Reduce Codebase Size: Patterns are typically beautiful and optimum solutions, so they need less coding than other solutions.

JavaScript Design Pattern Categories with Examples

Creational, structural, and behavioral design patterns are the primary classifications for grouping Javascript design patterns. These are distinct from one another based on the degree of complexity, level of detail, and scope of application to the overall system under design. The below section details the categories of design patterns in javascript with examples.

1. Creational Design Pattern

Creational Design Pattern is one of the Javascript design patterns. As the name implies, it offers a framework for creating objects or classes that improve the adaptability and reuse of the current code. It is used to regulate how users interact with the classes so that the developers are spared from dealing with the intricate construction. The process of making objects is the focus of the creational design concept.

Examples of creational design patterns examples are listed below.

  • Abstract Factory: Used to build objects without providing their concrete type.
  • Builder: Used to build a complex thing from small objects using a step-by-step technique.
  • Factory Method: Enables object creation without requiring a specific class name.
  • Prototype: A prototype is a model used to build a new item from an existing one.
  • Singleton: Used to create an example of an object once

2. Structural Design Patterns

The primary function of structural JS design patterns is to combine objects and classes into a more complex structure while ensuring that this structure is adaptable and practical. They play a crucial role in improving the code’s readability and ease of maintenance. Additionally, it makes sure that functions are appropriately divided and enclosed. It minimizes the contact between dependent items. 

Some of the examples of Structural Design patterns are listed below.

  • Adapter: By enclosing an interface around those existing classes, the adapter helps combine two incompatible types.
  • Composite: It combines several objects into one.
  • Bridge: This allows two components to work together with each other, while each has its own interface.
  • Decorator: It dynamically and at runtime extends the behavior of the object.
  • Facade: Provides a straightforward user interface for more intricate underlying components.
  • Flyweight: It brings down the price of complicated object models.
  • Proxy: It controls access to an underneath object by lowering costs, simplifying the setup, and providing a temporary interface.

3. Behavior Design Patterns

Design patterns for behavioral objects strongly emphasize the accountability and interaction of things. According to these design principles, the connections between the products’ exchange must be light while still permitting easy communication. Behavior design patterns govern the communication between classes. 

Examples of behavioral design patterns are listed below.

  • Chain of Responsibility: This represents the order of an object in a chain of processing.
  • Command: It creates objects that contain the parameters’ actions.
  • Interpreter: Defines grammatical representation of a  particular language.
  • Iterator: It progressively examines every component of an item without altering the representation underlying it.
  • Mediator: Because it is the sole class with in-depth knowledge of the other classes’ existing methods, the mediator establishes a loose coupling between them.
  • Memento: In Memento, an item is returned to its previous state.
  • Observer: It makes it possible for various observer objects to view an event.
  • State:  When an object’s internal state changes, its behavior can be modified.

4. Concurrency Design Patterns

Concurrency patterns are JS design patterns that deal with the multi-threaded programming model. Concurrent processing in a single-core system is accomplished by a procedure known as context-switching. In a multi-core context, parallelism can be used to achieve coexistence. 

Concurrency patterns are those categories of design patterns used in software engineering that address the multi-threaded programming model. An active object is one of the concepts in this group. A few examples of this group of patterns are as follows:

  • Guarded suspension: Guarded suspension is used in concurrent programming to manage tasks that necessitate both a lock as well as a precondition to be met before the action can be done.
  • Leaders/followers’ pattern: The Leader/Followers pattern offers a concurrency architecture in which many threads can de-multiplex events as well as dispatch event handlers that process shared I/O handles.
  • Monitor Object: Another concurrent design pattern that aids in running multi-threaded systems is the monitor object pattern.
  • Reactor pattern: The reactor design is an event management technique used to manage service requests given simultaneously to a service processor via one or more sources. The application handler then demultiplexes all incoming requests and sends them to the relevant request handlers synchronously.
  • Read-write lock pattern: A read-write lock pattern is primitive for synchronization, addressing one of the readers’ writers’ difficulties. For read-only tasks, an RW lock permits concurrent access; write actions need exclusive access.

5. Architectural Design Patterns

An architectural model is a broad, reusable response to a typical issue in software design within a specific environment. The design patterns address various software engineering concerns, including high availability, business risk mitigation, and performance constraints of computer technology. Frameworks for software have incorporated some architectural practices. 

Architectural design patterns in the javascript example include these:

  • Peer-to-peer Pattern: A single machine serves as the client and server in a peer-to-peer architecture. Each system, also known as a peer, transmits requests to the network’s peers while also receiving and servicing recommendations from other network peers.
  • Event-bus Pattern: An event bus is a JS design pattern that has the potential to streamline communication between various components. It is also known as publish/subscribe.
  • Model-view-controller Pattern: According to the MVC (model-view-controller design pattern), an application must include a data model, display information, and necessary information. Each of them must be divided into independent items according to the pattern.

6. Blackboard Patterns

The blackboard pattern of JS is a behavioral design pattern in software engineering that offers a computational foundation for formulating and constructing systems that combine vast and diverse specialized modules and perform complicated, non-deterministic control techniques.

7. Interpreter Patterns

This pattern proposes establishing grammar and an interpreter that employs representations to allow the system to understand any given sentence of a language.

8. Broker Patterns

The broker design is an architectural paradigm for structuring distributed software systems containing separated components that communicate via remote procedure calls. A broker element is in charge of organizing communication, including forwarding requests and relaying findings and exceptions.

Most extensive programs commonly employ design patterns, but it takes experience to recognize which one is preferable to another. Before developing any application, you should carefully consider each player and how individuals interact with others. After studying them, you need to recognize and apply the Prototype, Module, Observer, and Singleton designs.

The usage of design patterns by JavaScript developers is advantageous. Project maintainability and reducing extra effort in the development cycle are two important benefits of using design patterns. It is incorrect to assume that Js design patterns could replace developers even though they can offer solutions to complicated challenges, rapid development, and productivity.

BrowserStack supports JavaScript testing frameworks. Running automated testing on the BrowserStack device cloud saves time installing and maintaining device infrastructure. This will eventually result in a robust test framework that ensures higher testing coverage and a quality product for end customers.

While searching for testing platforms, selecting the one that integrates with your desired framework is critical. BrowserStack Automate, for instance, offers Javascript testing frameworks, making testing much easier and more efficient.

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