Cigniti Technologies Senior Data Engineer Interview Questions and Answers

Event loop is a mechanism that allows non-blocking I/O operations in a single-threaded environment.

• Event loop is used in programming languages like JavaScript and Python.

• It manages the execution of multiple tasks by prioritizing them based on their priority level.

• It continuously checks for new events and executes them in a loop.

• It allows for efficient handling of I/O operations without blocking the main thread.

• It is co...read more

let, var and const are used to declare variables in JavaScript with different scoping rules and mutability.

• let and var are used to declare variables that can be reassigned later, but var has function scope while let has block scope.

• const is used to declare variables that cannot be reassigned and have block scope.

• Using const does not mean the value is immutable, only the variable reference is.

• let and const were introduc...read more

Singleton design pattern restricts the instantiation of a class to one object.

• Ensures only one instance of a class exists

• Provides a global point of access to that instance

• Used when only one instance of a class is needed throughout the application

• Example: Database connection manager