40+ Full Stack Engineer Interview Questions and Answers

The task is to find the maximum size of a submatrix consisting of all 1's in a given binary-valued matrix.

• Iterate through each cell of the matrix

• For each cell, calculate the maximum size of a submatrix with that cell as the top-left corner

• Keep track of the maximum size encountered so far

• Return the maximum size

The task is to count the number of occurrences of the digit '1' in each number from 0 to N.

• Iterate through each number from 0 to N

• Convert each number to a string

• Count the number of occurrences of the digit '1' in the string representation of each number

• Return the total count of '1's

API stands for Application Programming Interface. It defines the methods and data formats that applications can use to communicate with each other.

• API is a set of rules and protocols that allows different software applications to communicate with each other.

• REST API is a type of API that follows the principles of REST (Representational State Transfer) architecture.

• Cloud computing refers to the delivery of computing services over the internet, including storage, databases, net...read more

Optimizing a query involves using indexes, limiting the result set, and avoiding unnecessary joins.

• Use indexes on columns frequently used in the query's WHERE clause

• Limit the result set by using pagination or filtering criteria

• Avoid unnecessary joins by denormalizing data or using subqueries

Find max continous sub array with unique elements in an array

• Use sliding window approach

• Keep track of unique elements in the window

• Update max length when a duplicate element is found

Dealing with ambiguous requirements and difficult challenges in a situation-based approach.

• Identifying and clarifying ambiguous requirements through effective communication

• Breaking down complex problems into smaller, manageable tasks

• Adapting to changing priorities and tight deadlines

• Collaborating with team members to brainstorm solutions

• Using critical thinking and problem-solving skills to find innovative solutions

• Managing expectations and balancing trade-offs between differe...read more

The clean up is performed in the useEffect hook in React.

• Clean up code is typically written in the return function of the useEffect hook.

• This is useful for unsubscribing from subscriptions, clearing intervals, or any other necessary clean up tasks.

• Example: useEffect(() => { // code here return () => { // clean up code here } }, [])

Implementing a retry mechanism in code to handle failures and retries automatically.

• Create a function that takes a function to execute and a maximum number of retries as parameters.

• Use a loop to execute the function and catch any exceptions that occur.

• If an exception occurs, decrement the number of retries left and retry the function.

• Example: function retry(func, maxRetries) { for(let i=0; i

Monolith is a single, large application while microservices are smaller, independent services.

• Monolith is a single, self-contained application where all components are interconnected.

• Microservices are smaller, independent services that communicate with each other through APIs.

• Monoliths are easier to develop and deploy but can become complex and harder to scale.

• Microservices offer better scalability, flexibility, and fault isolation but come with added complexity in managing m...read more

Yes, I have experience working with Docker and Kubernetes.

• I have used Docker to containerize applications for easier deployment and scaling.

• I have experience with Kubernetes for managing containerized applications in a clustered environment.

• I have set up Kubernetes clusters, managed deployments, services, and pods.

• I have worked on configuring networking, storage, and monitoring in Kubernetes.

• I have experience with Helm charts for packaging Kubernetes applications.

ES6 is the 6th version of ECMAScript, the standard for JavaScript.

• Introduced new features like let, const, arrow functions, classes, and modules.

• Improved syntax and added new methods to built-in objects.

• Supports destructuring, spread and rest operators, and template literals.

• Compatible with modern browsers and Node.js versions.

My journey started with self-learning and building small projects. Then I pursued a degree in computer science and gained professional experience in various companies.

• Started with self-learning and building small projects

• Pursued a degree in computer science

• Gained professional experience in various companies

• Continuously learning and improving skills

Callback hell is a situation where nested callbacks make the code difficult to read and maintain.

• It occurs when multiple asynchronous functions are called one after the other.

• It leads to deeply nested code that is hard to understand and debug.

• It can be avoided by using promises or async/await syntax.

• Example: nested callbacks in Node.js file system operations.

Data binding is the process of connecting data between the model and view in a web application.

• It allows for automatic updates to the view when the model changes and vice versa.

• There are two-way and one-way data binding.

• Examples include AngularJS's ng-model directive and React's state and props system.

Use GROUP BY and HAVING clause to find duplicate values in SQL.

• Use GROUP BY clause to group the data based on the column you want to check for duplicates.

• Use HAVING clause to filter out groups that have more than one entry, indicating duplicates.

• Example: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;

Microservices are a software development technique where applications are broken down into smaller, independent services that communicate with each other through APIs.

• Microservices are small, independent services that focus on specific business functions.

• Each microservice runs its own process and communicates with other services through APIs.

• Microservices can be developed, deployed, and scaled independently of each other.

• They promote flexibility, scalability, and resilience i...read more

div is a block-level element while span is an inline element in HTML.

• div is used to create a block-level element that starts on a new line and takes up the full width available, while span is used to create an inline element that does not start on a new line and only takes up as much width as necessary.

• div is typically used for grouping and styling larger sections of content, while span is used for styling smaller parts of text or inline elements within a block-level element....read more

Using fetch API to make requests to a sandbox environment for testing purposes.

• Use the fetch function to make HTTP requests to the sandbox URL

• Handle the response using promises and the .then() method

• Set the appropriate headers and request method for the API endpoint

• Parse the response data using JSON methods if needed

OOPs concepts revolve around the principles of encapsulation, inheritance, polymorphism, and abstraction in object-oriented programming.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (object).

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: Ability for objects of different classes to respond to the same message.

• Abstraction: Hiding the complex implementation details and showing only the nece...read more

Databinding is a technique to establish a connection between UI and data source.

• Databinding allows automatic synchronization of data between UI and data source.

• It reduces boilerplate code and makes code more readable and maintainable.

• Databinding can be one-way or two-way depending on the requirement.

• Examples of databinding frameworks are AngularJS, React, Vue.js, etc.

Writing tests for Go programming language

• Use the testing package in Go to write unit tests

• Create test files with _test.go suffix for each package to be tested

• Use functions like TestXxx(t *testing.T) to define test cases

• Run tests using 'go test' command in the terminal

I handle work pressure by prioritizing tasks, taking breaks, and seeking support when needed.

• Prioritize tasks based on deadlines and importance

• Take short breaks to recharge and refocus

• Communicate with team members or supervisors for help or guidance

• Practice stress-relief techniques like deep breathing or mindfulness

• Maintain a healthy work-life balance to prevent burnout

React is optimised due to virtual DOM, one-way data binding, and component-based architecture.

• Virtual DOM allows React to update only the necessary components, improving performance.

• One-way data binding ensures that data flows in a single direction, reducing the risk of bugs.

• Component-based architecture promotes reusability and modularity, making code easier to maintain.

• React's use of JSX allows developers to write HTML-like code within JavaScript, improving readability and p...read more

Indexes in MongoDB are used to improve the performance of queries by allowing the database to quickly locate and retrieve specific documents.

• Indexes can be created using the createIndex() method in MongoDB.

• Indexes can be created on a single field or a combination of fields.

• Indexes can be unique, sparse, or compound.

• Examples: db.collection.createIndex({ field: 1 }), db.collection.createIndex({ field1: 1, field2: -1 })

Duplexes in Node.js are streams that can both read from and write to.

• Duplex streams are instances of the `stream.Duplex` class in Node.js

• They combine the features of Readable and Writable streams

• Examples of Duplex streams include TCP sockets and zlib streams

Scrum is an agile project management framework that emphasizes teamwork, accountability, and iterative progress.

• Scrum is based on the principles of transparency, inspection, and adaptation.

• It involves breaking down a project into small, manageable tasks called user stories.

• Scrum teams work in short iterations called sprints, typically 2-4 weeks long.

• Daily stand-up meetings are held to discuss progress, challenges, and plans for the day.

• Scrum also includes regular sprint revie...read more

Mongoose Lookup is a feature in Mongoose that allows for populating documents from another collection.

• Mongoose Lookup is used to reference documents from another collection in MongoDB.

• It is similar to a SQL join operation.

• Example: User schema referencing a Post schema using Mongoose Lookup.