Cognizant Project Associate Interview Questions, Process, and Tips

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine.

• Node.js allows for server-side scripting and event-driven programming.

• It has a large and active community with a vast number of libraries and modules available.

• Node.js is known for its scalability and high performance.

• Cons include potential security vulnerabilities and difficulty in debugging asynchronous code.

• Node.js is commonly used for web applic...read more

var, let & const are JavaScript keywords used for declaring variables with different scoping rules.

• var has function scope and can be redeclared and updated

• let has block scope and can be updated but not redeclared

• const has block scope and cannot be updated or redeclared

• Use const for values that won't change, let for values that will change, and var for legacy code

• Example: var x = 10; let y = 'hello'; const z = true;

Spread operator is a syntax in JavaScript that allows an iterable such as an array or string to be expanded into individual elements.

• It is denoted by three dots (...)

• It can be used to concatenate arrays

• It can be used to copy an array

• It can be used to pass arguments to a function

• It can be used to create a new object with properties of an existing object

• Example: const arr1 = [1, 2, 3]; const arr2 = [...arr1, 4, 5, 6];

• Exa...read more

Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope.

• Variables declared with var are hoisted to the top of their scope.

• Function declarations are also hoisted to the top of their scope.

• Function expressions are not hoisted.

• Hoisting can lead to unexpected behavior and bugs in code.

• Example: console.log(x); var x = 5; // Output: undefined

Closure is a feature in programming languages that allows a function to access variables outside its scope.

• Closure is used to create private variables and methods in object-oriented programming.

• It is also used to create callbacks and event handlers in JavaScript.

• A closure is created when a function is defined inside another function and the inner function references variables from the outer function.

• The outer function ...read more

Single threaded operation refers to the execution of a program using only one thread of execution.

• Single threaded programs can only perform one task at a time.

• They are simpler to write and debug than multi-threaded programs.

• Examples of single threaded programs include most console applications and simple scripts.

• Single threaded programs can be less efficient than multi-threaded programs when dealing with complex tasks

package.json is a file used in Node.js projects to manage dependencies and configuration.

• Contains metadata about the project such as name, version, and dependencies

• Used by package managers like npm to install and manage dependencies

• Can include scripts to automate tasks like testing and building

• Example: {"name": "my-project", "version": "1.0.0", "dependencies": {"express": "^4.17.1"}}

Node.js was chosen for its event-driven, non-blocking I/O model and scalability.

• Node.js is well-suited for real-time applications that require high concurrency and low latency.

• Java is better suited for large-scale enterprise applications that require strict type checking and robust error handling.

• Node.js has a large and active community with many useful libraries and frameworks.

• Node.js is lightweight and easy to deploy...read more

Microservices is an architectural style where an application is composed of small, independent services that communicate with each other.

• Microservices are independently deployable and scalable.

• Each microservice performs a specific business function.

• Communication between microservices is usually through APIs.

• Microservices can be developed using different programming languages and technologies.

• Examples of companies using...read more

HTTP verbs are used to specify the type of action to be performed on a resource.

• GET - retrieve information from the server

• POST - submit data to be processed by the server

• PUT - update a resource on the server

• DELETE - delete a resource on the server

• HEAD - retrieve headers from the server

• OPTIONS - retrieve the supported HTTP methods for a resource

• PATCH - update a resource partially on the server

Paging is a technique used to divide large data sets into smaller chunks. Lazy loading is a technique used to load data on demand.

• Paging is used to improve performance by reducing the amount of data loaded into memory at once.

• Lazy loading is used to improve performance by only loading data when it is needed.

• Paging is commonly used in web applications to display large amounts of data in a user-friendly way.

• Lazy loading ...read more

To deploy an application in cloud, follow these steps:

• Choose a cloud provider (Azure/AWS)

• Create an account and login to the cloud console

• Create a virtual machine or container to host the application

• Upload the application code and necessary dependencies

• Configure the application settings and environment variables

• Test the application and make necessary adjustments

• Deploy the application to the cloud

• Monitor the application