Corel Pharma Chem Interview Questions and Answers

Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Used to control access to a shared resource such as a database connection or a logger instance

• Implemented by creating a class with a method that creates a new instance only if one doesn't exist, and returns the existing instance if it does

• Commonly used in React applications for managing global state with Redux or Context API

Strategy pattern is a behavioral design pattern that allows selecting an algorithm at runtime.

• Used strategy pattern in a shopping cart application to dynamically apply different discount strategies based on user type (e.g. regular customer, premium customer)

• Implemented strategy pattern in a payment processing system to handle different payment methods (e.g. credit card, PayPal, Apple Pay)

• Utilized strategy pattern in a traffic management system to dynamically switch between di...read more

Virtual DOM is a lightweight copy of the actual DOM in React, used for efficient updates.

• Virtual DOM is a concept where a lightweight copy of the actual DOM is created in memory.

• React uses the virtual DOM to efficiently update the actual DOM when there are changes in the application state.

• By comparing the virtual DOM with the actual DOM, React determines the minimal number of changes needed to update the UI.

• This helps in improving performance by reducing the number of DOM man...read more

SCSS provides benefits such as variables, nesting, mixins, and inheritance for more efficient and maintainable CSS code.

• Variables allow for easy reuse of values throughout stylesheets.

• Nesting helps to organize CSS rules in a more intuitive way.

• Mixins enable the reuse of styles across different elements.

• Inheritance allows styles to be inherited from one selector to another.

• SCSS can help improve code readability and maintainability.

Dependency injection is a design pattern where components are provided with their dependencies rather than creating them internally.

• Dependency injection helps in making components more modular and easier to test.

• It allows for better separation of concerns by decoupling the creation of dependencies from their usage.

• There are different types of dependency injection such as constructor injection, setter injection, and interface injection.

• Example: In React, dependency injection c...read more