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NodeJS Interview Questions Answers

Question 1 : What is Node.js?

Answer 1 : Node.js is a very popular scripting language that is primarily used for server-side scripting requirements. It has numerous benefits compared to other server-side programming languages out there, the most noteworthy one being the non-blocking I/O.

Question 2 : Briefly explain the working of Node.js.

Answer 2 : Node.js is an entity that runs in a virtual environment, using JavaScript as the primary scripting language. It uses a simple V8 environment to run on, which helps in the provision of features like the non-blocking I/O and a single-threaded event loop.

Question 3 : Where is Node.js used?

Answer 3 : Node.js is used in a variety of domains. But, it is very well regarded in the design of the following concepts: • Network application • Distributed computing • Responsive web apps • Server–Client applications Next up on these Node js interview questions, you have to understand a very vital difference. Read on.

Question 4 : Why is Node.js single-threaded?

Answer 4 : Node.js works on the single-threaded model to ensure that there is support for asynchronous processing. With this, it makes it scalable and efficient for applications to provide high performance and efficiency under high amounts of load.

Question 5 : What are the different API functions supported by Node.js?

Answer 5 : There are two types of API functions. They are as follows: • Synchronous APIs: Used for non-blocking functions • Asynchronous APIs: Used for blocking functions

Question 6 : What is the difference between synchronous and asynchronous functions?

Answer 6 : Synchronous functions are mainly used for I/O operations. They are instantaneous in providing a response to the data movement in the server and keep up with the data as per the requirement. If there are no responses, then the API will throw an error. On the other hand, asynchronous functions, as the name suggests, work on the basis of not being synchronous. Here, HTTP requests when pushed will not wait for a response to begin. Responses to any previous requests will be continuous even if the server has already got the response. Next among the Node js questions, we have to check out about control flow function.

Question 7 : What is the control flow function?v

Answer 7 : The control flow function is a common code snippet, which executes whenever there are any asynchronous function calls made, and they are used to evaluate the order in which these functions are executed in Node.js.

Question 8 : Why is Node.js so popular these days?

Answer 8 : Node.js has gained an immense amount of traction as it mainly uses JavaScript. It provides programmers with the following options: • Writing JavaScript on the server • Access to the HTTP stack • File I/O entities • TCP and other protocols • Direct database access

Question 9 : What is an event loop in Node.js?

Answer 9 : When running an application, callbacks are entities that have to be handled. In the case of Node.js, event loops are used for this purpose. Since Node.js supports the non-blocking send, this is a very important feature to have. The working of an event loop begins with the occurrence of a callback wherever an event begins. This is usually run by a specific listener. Node.js will keep executing the code after the functions have been called, without expecting the output prior to the beginning. Once, all of the code is executed, outputs are obtained and the callback function is executed. This works in the form of a continuous loop, hence the name event loop.

Question 10 : What are the asynchronous tasks that should occur in an event loop?

Answer 10 : Following are some of the tasks that can be done using an event loop asynchronously: • Blocking send requests • High computational requirement • Real-time I/O operations


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