What is Known as Gang of Four?

Top 30 Interview Questions for Design Patterns in JavaScript

1. What is Design Pattern in JavaScript?...

1. What is Design Pattern in JavaScript?

A design pattern is the reusable solution to the common problem in software design and software development. It is basically a general template that can be applied to solve a particular design problem in code....

2. Types of Design Pattern in JavaScript?

There are mainly three types of design patterns:...

3. What are the Main advantages of using design pattern in JavaScript?

There are so many advantages of using design pattern let’s see some of them are:...

4. How does the Module design pattern work in JavaScript?

The module pattern is used in JavaScript to provide a structure for organizing code into reusable and maintainable modules. It provides a way to encapsulate variables and functions within a single unit of code, making it easier to manage complex applications....

5. What is the Observer pattern?

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6. Explain the Singleton design pattern in JavaScript

The Observer pattern defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically....

7. How does the Strategy pattern work in JavaScript?

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8. Explain the Factory Design Pattern.

The Singleton pattern ensures that a class has only one instance and provides a global point of access to that instance. It is often used for logging, driver objects, caching, thread pools, or database connections....

9. How does the Prototype pattern work?

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10. What is the Decorator pattern in JavaScript?

Strategy pattern is a behavioral design pattern that allows the behavior of an object to be selected at runtime. It is one of the Gang of Four (GoF) design patterns, which are widely used in object-oriented programming....

11. What is Known as Gang of Four?

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12. Define the MVC (Model-View-Controller) pattern in JavaScript

The factory method is a creational design pattern, i.e., related to object creation. The Factory Method pattern is used to create objects without specifying the exact class of object that will be created. This pattern is useful when you need to decouple the creation of an object from its implementation....

13. Which is the most common used design pattern in javascript?

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14. What do you understand by Dependency Injection pattern and how do you implemented it in JavaScript?

The Prototype pattern creates new objects by copying an existing object, known as the prototype. It is useful when creating many similar objects....

15. Explain the Publish-Subscribe pattern and provide an example in JavaScript.

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16. How is the Strategy pattern different from the State pattern?

The Decorator pattern allows behavior to be added to an individual object, either statically or dynamically, without affecting the behavior of other objects from the same class....

17. Explain the Proxy pattern in JavaScript.

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18. How does the Template Method pattern work?

The four authors who published the book Design Patterns Elements of Reusable Object-Oriented Software are known as Gang of Four. The name of four authors are Erich Gamma, Ralph Johnson, Richard Hel, and John Vlissides....

19. Explain the Chain of Responsibility pattern and provide an example in JavaScript.

MVC is an architectural design pattern that separates an application into three interconnected components: Model (data and business logic), View (user interface), and Controller (handles user input and updates the model and view)....

20. How is the Factory pattern different from the Abstract Factory pattern?

One of the most commonly used design patterns in JavaScript is the Module Pattern. The Module Pattern is a way to encapsulate a set of functionalities, creating a modular and organized structure for your code. It leverages closures to provide private and public members, allowing for better control over the scope and access to variables and functions....

21. Describe the Proxy pattern and provide a real-world example in JavaScript.

The Dependency Injection pattern involves supplying an external dependency to a software component rather than creating it within the component. In JavaScript, this can be achieved through constructor injection or property injection....

22. Explain the Command pattern and provide a use case in JavaScript.

The Publish-Subscribe pattern, also known as the Observer pattern, allows multiple objects to listen and respond to events. This pattern is used to establish communication between objects without them being directly coupled....

23. Describe the Memento pattern with example.

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24. What is the Revealing Module pattern?

The Strategy pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable and the State pattern allows an object to alter its behavior when its internal state changes....

25. How does the State Pattern work, and when it is used in JavaScript?

The Proxy pattern provides a surrogate or placeholder for another object to control access to it. It is useful for implementing lazy loading, access control, and logging....

26. Explain the Flux architecture and how it utilizes the Observer Pattern.

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27. How does Module Pattern differ from the Revealing Module Pattern?

The Template Method pattern defines the skeleton of an algorithm in the superclass but lets subclasses override specific steps of the algorithm without changing its structure....

28. Differentiate between the Factory and Abstract Factory Patterns

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29. Explain the Flux Pattern and its relationship with React

The Chain of Responsibility pattern passes a request along a chain of handlers. In JavaScript, this is often used in event handling where multiple objects can handle an event, and the event is passed through a chain of handlers until one handles it....

30. Example of Revealing Module pattern in JavaScript

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Conclusion

The Factory pattern involves creating objects through a common interface, while the Abstract Factory pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes....