Node.js is a popular open-source, cross-platform runtime environment for executing JavaScript code outside of a browser. It's often used to build server-side applications, APIs, and microservices. If you're preparing for a Node.js job interview, you may want to familiarize yourself with some commonly asked Node.js interview questions. In this article, we'll cover some Node.js interview questions that you may encounter during your job search. These questions cover a range of topics, from the basics of Node.js to more advanced concepts like event-driven programming, callbacks, and more. So, let's dive in and explore some Node.js interview questions!
Ans: Node.js is a Server side scripting that is utilized to construct versatile projects. Its various points of interest over other server-side dialects, the noticeable being non-blocking I/O.
Ans: Node.js takes a shot at a v8 domain, it is a virtual machine that uses JavaScript as its scripting dialect and accomplishes high yield by means of non-blocking I/O and single-strung occasion circle.
Ans: I/O is the shorthand for information and yield, and it will get to anything outside of your application. It will be stacked into the machine memory to run the program, once the application is begun.
Ans: In PC programming, occasion-driven writing computer programs is a programming worldview in which the stream of the program is controlled by occasions like messages from different projects or strings. It is an application engineering procedure partitioned into two segments 1) Event Selection 2) Event Handling
Ans: Node.js can be utilized for the accompanying purposes
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Ans: It gives a simple method to manufacture versatile system programs
Ans: The two sorts of API works in Node.js are
Ans: A nonexclusive bit of code that keeps running in the middle of a few nonconcurrent work calls is known as control stream work.
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Ans: For async handling, Node.js was made expressly as an investigation. It is trusted that more execution and versatility can be accomplished by doing async handling on a solitary string under normal web loads than the commonplace string-based usage.
Ans: Indeed – it does. Download the MSI installer from http://nodejs.org/download/
Ans: No, you can't get to DOM in hub.
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Ans: Node.js is rapidly picking up consideration as it is a circle-based server for JavaScript. Node.js enables the client to compose the JavaScript on the server, which approaches things like HTTP stack, document I/O, TCP and databases.
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Ans: To process and handle outer occasions and to change over them into callback summons an occasion circle is utilized. In this way, at I/O calls, node.js can change starting with one demand and then onto the next.
Ans: By following advances you can async Node.js
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Advantages
Disadvantages
Ans:Node.js takes care of this issue by putting the occasion-based model at its centre, utilizing an occasion circle rather than strings.
Ans: The contrast between Node.js and Ajax is that Ajax (short for Asynchronous Javascript and XML) is a customer-side innovation, regularly utilized for refreshing the substance of the page without reviving it. While,Node.js is Server Side Javascript, utilized for creating server programming. Node.js does not execute in the program but rather by the server.
Ans: Accentuating on the specialized side, it's a touch of test in Node.js to have one process with one string to scale up on the multi-center server.
Ans: In node.js "non-blocking" implies that its IO is non-blocking. Node utilizes "libuv" to deal with its IO in a stage freethinker way. On Windows, it utilizes consummation ports for Unix it utilizes epoll or kqueue and so on. Thus, it makes a non-blocking demand and upon a demand, it lines it inside the occasion circle which calls the JavaScript 'callback' on the primary JavaScript string.
Ans: Summon "require" is utilized for bringing in outside libraries, for instance, "var http=require ("HTTP")". This will stack the HTTP library and the single sent-out protest through the http variable.
Ans: "Express" is the most widely recognized structure utilized as a part of node.js
Ans: Callback work is utilized as a part of node.js to manage different solicitations made to the server. On the off chance that you have a substantial record that will be set aside quite a while for a server to peruse and on the off chance that you don't need a server to get take part in perusing that huge document while managing different solicitations, get back to work is utilized. Getting back to work enables the server to manage pending solicitation first and call a capacity when it is done.
Ans: “Callback hell” refers to heavily nested callbacks that have become unwieldy or unreadable.
An example of heavily nested code is below:
The primary method to fix callback hell is usually referred to as modularization. The callbacks are broken out into independent functions which can be called with some parameters.
Ans: Node.js, in its essence, is a single-thread process. It does not expose child threads and thread management methods to the developer. Technically, Node.js does spawn child threads for certain tasks such as asynchronous I/O, but these run behind the scenes and do not execute any application JavaScript code, nor block the main event loop.
If threading support is desired in a Node.js application, there are tools available to enable it, such as the ChildProcess module.
Ans: Since Node.js is by default a single-thread application, it will run on a single processor core and will not take full advantage of multiple core resources. However, Node.js provides support for deployment on multiple-core systems, to take greater advantage of the hardware. The Cluster module is one of the core Node.js modules and it allows running multiple Node.js worker processes that will share the same port.
Ans: Node.js core modules, as well as most of the community-published ones, follow a pattern whereby the first argument to any callback handler is an optional error object. If there is no error, the argument will be null or undefined.
A typical callback handler could therefore perform error handling as follows:
Ans: If you use Express (High performance, high-class web development for Node.js), you can do this:
HTML:
<form method="post" action="/"> <input type="text" name="user[name]"> <input type="text" name="user[email]"> <input type="submit" value="Submit"> </form>
Javascript:
app.use(express.bodyParser();
app.post('/', function(request, response){
console.log(request.body.user.name); console.log(request.body.user.email);
});
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