St. Theresa's Hospital Interview Questions and Answers

Array map transforms each element of an array, array filter filters elements based on a condition, and for each iterates over each element.

• Array map returns a new array with transformed elements

• Array filter returns a new array with elements that pass a condition

• For each does not return anything, it just iterates over each element

• All three methods do not modify the original array

• Examples: map - doubling each element of an array, filter - getting all even numbers from an array,...read more

Dependency injection is a design pattern used to remove hard-coded dependencies and make code more flexible and testable.

• Dependency injection is a way to provide objects with the dependencies they need to function.

• It involves creating objects with their dependencies injected from outside rather than hard-coding them.

• This makes code more flexible, reusable, and testable.

• There are three types of dependency injection: constructor injection, setter injection, and interface inject...read more

useMemo is used to memoize a value, while useCallback is used to memoize a function.

• useMemo is used to optimize expensive computations by caching the result and returning it if the inputs haven't changed.

• useCallback is used to optimize expensive function creation by caching the function instance and returning it if the inputs haven't changed.

• useMemo returns a value, while useCallback returns a memoized function.

• useMemo is useful for memoizing values that are expensive to comp...read more

ERD stands for Entity Relationship Diagram, a visual representation of entities and their relationships in a database.

• ERD is used to design and model databases.

• It shows the relationships between entities, such as one-to-one, one-to-many, and many-to-many.

• Entities are represented as rectangles, and relationships are represented as lines connecting them.

• Attributes of entities are also shown in ERD.

• Example: A customer can have many orders, but an order can only belong to one cus...read more

Redux is a predictable state container for JavaScript apps.

• Redux is commonly used with React to manage the state of an application.

• It helps in maintaining a single source of truth for the state.

• Actions are dispatched to update the state in a predictable way.

• Reducers are used to specify how the state changes in response to actions.

• Selectors can be used to extract specific pieces of state from the store.

• Example: Redux is used in e-commerce websites to manage the shopping cart s...read more

Serverless is a cloud computing model where the cloud provider manages the infrastructure and automatically allocates resources.

• Serverless allows developers to focus on writing code without worrying about infrastructure management.

• It is event-driven and scales automatically based on demand.

• Examples include AWS Lambda, Azure Functions, and Google Cloud Functions.