Top 10 Node.js interview questions and answers in 2022

Below are the main benefits of using Node.js:

• The APIs in Node.js are asynchronous which means that they do not cause blockers. This happens due to the Node.js server not waiting for the return of data once an API has been called. It moves on to the next API. Instead, there is a notification mechanism that gets the response from the prior API call. Thus, we can also say that Node.js is event-driven.
• Node.js is powered by the Google Chrome V8 JavaScript Engine. This makes code execution in the Node.js library super fast.
• Node.js is based on a single-thread model with event looping. The event mechanism in the Node.js library makes it highly scalable because it prevents blockers on the server as compared to other servers that can only handle limited requests. In Node.js, the single thread program can service copious requests compared to something like Apache HTTP Server.
• Because of the event mechanism in Node.js, there is no buffering. Instead, the data output occurs in chunks.

<user-directory>/npm directory stores the globally installed dependencies. While these dependencies can be used in the Command Line Interface or CLI function of all Node.js libraries, they cannot be directly imported in the Node application with the require() command. If you want to globally install a dependency, you can use the -g flag.

Because of the event mechanism in Node.js, a callback function is called every time an event starts. This prevents blocking in Node.js.

Because of the single-thread model, Node.js prevents bottlenecks and aids programmers in easily writing the code. Internally, there are several POSIX threads for different I/O operations like File, DNS, etc. So, when Node receives an I/O request, it uses one of these threads for the I/O operation. Once the operation is complete, the result joins the event queue. Because of the event mechanism, the event loop starts after each event, checks the queue, and if Node’s execution stack is free, then the loop adds the queue result to it, thus, managing concurrency.

One of the main applications where Node.js can be used is building real-time web applications. Apart from this, distributed systems for sub-programming collection can also use Node.js. It can be used in general applications as well as complex network applications. One can also use Node.js to create, read, write, or close server files.

In general servers, multiple threads tend to load the system with tasks. These tasks tend to engage the cycles in scheduling the threads and thus, bring latency to the server as well as impose a limit on the number of requests that can be handled, thereby affecting scalability.

The Control function is a generic code that can be run among multiple asynchronous function calls. Due to this code being compatible with the function calls, it can be used for several tasks.

With the help of the Modularize option, users can avoid situation callbacks. The Modularize option splits the callbacks into smaller functions that are independent of each other. However, to make these functions work cohesively, they can be also joined at a later stage.

REPL stands for Read Eval Print Loop. REPL performs tasks related to reading, executing, printing, and looping. The server contains several ad-hoc Java statements that REPL can help execute. With REPL, the JavaScript can enter the shell post directly and reliably perform tasks like debugging, testing, and experimenting.

No technology comes without a few disadvantages. Node.js also has a few drawbacks. The main drawback is that Node.js responses can be greatly blocked if an intensive CPU computation is used. In such cases, the multiple thread options are better but they are sluggish in performance. Moreover, if a relational database is used with Node.js, it behaves strangely, preventing favorable outcomes that the users can be sure of. Since Node.js does not support multiple threads, it is better suited for lightweight applications but not large-scale or heavy applications.