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By asking this question, the hiring manager will get an idea of the type and COMPLEXITY of past projects you have completed. You should clearly state the problems you encountered and the steps you took to overcome them. In addition, you can talk about the lessons you learned from the issue.

A potential employer doesn't expect applicants to know everything, whether they're freshers or experienced. However, a well-prepared and enthusiastic candidate will undoubtedly stand out. In a full stack developer interview, candidates should be able to DEMONSTRATE excellent organizational skills and precision in their work. Also, honesty and transparency pay DIVIDENDS over the long run.

In this article, we have covered the top 30+ Full-Stack developer interview questions & ANSWERS for freshers and experienced candidates so you can succeed in your next full-stack developer interview. Questions like those listed above are quick, insightful, and provide key CUES that are vital to the interview process. If you review frequently asked full stack developer interview questions and answers, you increase your chances of getting hired. Make sure you review all the questions and answers.

We hope to have cleared up your doubts and guided you in the right direction. Good luck with your full stack developer interview!

With this question, the interviewer can figure out the methodology of the full stack web developer and determine if he is SHARP and precise in selecting the right TOOLSET.

While explaining the reasons for choosing a PARTICULAR toolset, you should be as specific as possible. You must demonstrate that you can develop both the front and backend of the web APPLICATION. Having more experience on one side of the development game than the other is okay, but you should show you are capable of handling both ENDS of the application.

The propagation of events inside the DOM (Document Object Model) is known as 'Event Flow' in JavaScript. The event flow defines the order or sequence in which a particular WEB page receives an event. Accordingly, event flow (propagation) in JS is dependent on the following aspects:

• Event Bubbling: With Event Bubbling, the event is captured and handled first by the innermost element, and then propagates to the outermost element. Events PROPAGATE up the DOM TREE from child elements until the topmost element is handled.
• Event Capturing: With Event Capturing, the event is captured and handled first by the outermost element, and then propagates to the innermost element. Event cycles propagate starting with the wrapper elements and ENDING with the target elements that initiated the event cycle.

The following diagram will help you to understand the event propagation life cycle.

One of the most popular features of ES6 is the "arrow functions" (also KNOWN as "FAT arrow functions"). Arrow functions are a NEW way to write CONCISE functions. Arrow functions offer a compact alternative to TRADITIONAL function expressions, but they have limitations and cannot be used in every case.

The following is an ES5 function:

The same function can also be expressed as an arrow function in ES6 as follows:

Differences & Limitations:

• Has no bindings to 'this' or 'super', so it shouldn't be used as a method.
• Has no new.target keyword.
• The call, apply, and bind methods are not suitable since they rely on establishing scope.
• Not suitable for use as constructors.
• Not possible for an arrow function to use the yield keyword within its body, etc.

Before ES6, VARIABLE declarations were only possible using var. With ES6, we got let and const. Both let and const declarations are block-scoped, i.e., they can only be accessed within the " { } " surrounding them. On the other hand, var doesn't have such a restriction. Unlike var, which can be accessed before its declaration, you cannot access the let or const variables until they are initialized with some value. Temporal Dead Zone is the time from the beginning of the execution of a block in which let or const variables are declared until these variables are initialized. If anyone tries to access those variables during that zone, JAVASCRIPT will always throw a reference error as GIVEN below.

Both let and const variables are in the TDZ from the moment their enclosing scope STARTS to the moment they are declared.

Developers prefer to develop Android applications by utilizing a software architecture PATTERN. Architecture patterns allow you to express and define a structural schema for software systems. Developers can easily maintain the software and continue to add features to the software in the future. The two most popular android architecture patterns are MVC (Model View Controller) and MVP (Model View Presenter).

As long as the data within the API is accessible to the public, it will technically not be possible to completely prevent data scraping. It is possible, however, to minimize bot activity (automated computer programs on the internet that perform certain tasks) by throttling or rare limiting. Rare limiting will be able to prevent a certain DEVICE from making an unlimited number of requests within a DEFINED time. If too many requests are made beyond the defined limit, a 429 Too Many ATTEMPTS HTTP error is thrown. It is vital to RECORD more than just the IP address of the device since the IP address is not unique to each device and can stop the whole network from accessing the API.

MEAN stands for MongoDB, ExpressJS, AngularJS, and Node.js. It is a COLLECTION of JAVASCRIPT-based technologies for developing web APPLICATIONS. Despite being a stack of different technologies, all of them are based on the JavaScript language. It is an ideal solution for BUILDING dynamic websites and applications as it is a very user-friendly stack. With this free and open-source stack, you can QUICKLY and easily build web-based prototypes.

APIs (APPLICATION Programming Interfaces) are sets of rules and protocols that define how software programs or devices can communicate with each other. APIs that conform to the design principles of REST, or representational state transfer, are known as REST APIs. REST APIs may also be referred to as RESTFUL APIs. Using RESTful APIs, developers can CREATE requests and RECEIVE responses via an HTTP request. REST API can also be USED for mapping data from a cloud platform to a data warehouse or vice versa.

GET and POST are two different HTTP request methods.

Callback functions are functions that can be passed to another function as ARGUMENTS and executed there to complete a routine or action. Those functions depend on ONE another, so it could get quite messy with so many callback functions nested in so many layers. This is what is referred to as callback hell.

As an alternative to callbacks in JavaScript, promises are USED to handle asynchronous operations. In addition to handling MULTIPLE asynchronous operations, they provide better error handling than callbacks. Promises can be a better way for a user to read the code effectively and efficiently, especially when that particular code performs multiple asynchronous operations. The Promise object represents the result of an asynchronous operation (or its failure) and the resulting value. The promise is in one of the following STATES:

• Pending: In its initial state, neither fulfilled nor rejected.
• Fulfilled: Indicating that the operation was successful.
• Rejected: Indicating that the operation failed.

If a connection is opened and forgotten about, this is known as a "leak" SINCE each time it occurs, a connection is no longer available for REUSE. Connection leaks occur when some database requests or transactions are not closed properly or are not committed, causing the connections to be abandoned and closed permanently.

Java developers commonly experience Connection Leaks when using Connection Pools. In the case where there is a section of code that fails to close a connection properly, a connection will leak from the pool each time the section of code is executed. Eventually, if this SITUATION CONTINUES, the pool will run out of connections, which is known as Pool Exhaustion. The application will hang once all available connections have been leaked. We can fix this by closing the connection and paying particular attention to any error handling code.

NORMALIZATION and denormalization are the two main methods of altering the structure of a database.

In functional programming, referential transparency is the KEY differentiating factor.  An expression is considered referential TRANSPARENT if it can be replaced or SUBSTITUTED with the corresponding value it computes or vice-versa without affecting the PROGRAM’s result.

Example: Imagine that we have an expression called four: val four= add(1,3)

If four is used anywhere in our code, it can safely be replaced with add(1,3), 1 + 3 or 4 wherever it appears. Thus, all the EXPRESSIONS below are equivalent in meaning and output:

If we can swap back-and-forth between these expressions anytime, anywhere, without altering their meaning or output, then an expression is referentially transparent.

IoC (Inversion of Control), as the name suggests, is a DESIGN principle in software engineering. With IoC, different kinds of controls can be inverted in an object-oriented design to attain loose coupling. The term "controls" refers to any other responsibilities a CLASS may have other than its primary responsibility. These include controlling the flow of an application, controlling the creation of objects, or controlling the binding and creation of dependent objects. IoC allows CLASSES to be loosely coupled, MAKING testing and maintenance easier. 

Today, the software is rapidly created and features are often changed based on customer needs, and then it is deployed into production. Each organization has its UNIQUE way of getting new APPLICATIONS into the production environment. Most organizations follow the standard deployment and RELEASE strategies such as Blue-Green and Rolling Deployment.

• Blue-Green Deployment Strategy:

A deployment strategy like this creates two separate infrastructure environments i.e., blue and green. A blue environment contains older code (old version), while a green environment (production) contains the latest code (new version). There is only ONE live production environment at any given time.

Example: For instance, the green environment is live and is receiving all user traffic, while the clone (blue) is idle. Once a new version of an application is ready for release, it can be deployed to the blue environment for TESTING. As soon as the new release passes testing, application traffic is switched from green to blue. Blue then becomes the live production environment, and Green becomes idle, ready for testing the next release.

• Rolling Deployment Strategy

Using this deployment strategy, old versions of an application are completely replaced with the new versions by completely replacing the infrastructure on which they run.

Example: When a new version must be deployed to all nodes, the new version is deployed to the first node while all other nodes handle end-user traffic. As soon as the new version is successfully installed on the first node, it will begin managing end-user traffic while the new version is being installed on the second node. The process is repeated until all nodes have been successfully upgraded to the new version.