9 QUESTIONS YOU CAN ASK NEST JS APP DEVELOPER DURING THE INTERVIEW

NestJS is a JavaScript-based tool that was developed as a framework to facilitate the development of scalable, testable server-side applications. It is an open-source Node.js framework that is flexible, extensible, and progressive for creating backend systems. NestJS supports databases like MongoDB, MySQL, and PostgreSQL, and it is the fastest-growing Node.js framework in TypeScript. To get the most of Nest Js, hire Nest Js app developers who are experienced in this field.

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Questions you can ask NestJS app developer during the interview

To hire Nest js app developers, there are some appropriate questions to ask during the interview.

What is Event-driven programming?

This is a form of programming that is based on events. Events can be a mouse click, a keypress, etc. When an event happens the information required is retrieved by issuing callbacks that are already registered with the element to the main server. This kind of programming majorly follows a publish-subscribe pattern.

What is Demultiplexer?

The Demultiplexer referred to as Event Notification Interface, provides Event Que by gathering information from events and queues Input and Output events CPU time is wasted.

Explain in Node Js, what the leading security implementations are

The primary security management implementation methods within Node JS are authentication and error handling.

Differentiate between createReadStream and readFile in Node.js?

readFile refers to a fully buffered process in which a response is only returned when the complete file is pushed into the buffer and read. In contrast, createReadStream refers to a process only partly buffered and is treated as an event series with the whole file split into chunks, processed, and then sent back as a response one after the other. readFile is a more memory-intensive process and can be slow, especially with large files, whereas createReadStream is faster for processing large files.

Why is Node.js Single-threaded?

Node.js is single-threaded for asynchronous (out of synch) processing to boost performance and scalability.

Describe the Event loop in Node.js?

The Event loop in Node.js handles all asynchronous callbacks in an application. It is an essential part of Node.js as Node.js (or JavaScript) is a single-threaded, event-driven language. A listener can be attached easily to an event with the callback provided by the listener when the event occurs. All callbacks functions are queued on a loop and then executed after the other after the response has been received. When functions like setTimeout, fs.readFile, and HTTP.get are called, the event loop is executed by Node.js, and it continues with further code without waiting for output. Once the operation is finished, it receives the output and then runs the callback function.

Describe Reactor Pattern in Node.js?

Reactor Pattern is a concept of non-blocking Input and Output operations in Node.js. Through this pattern, a handler (call back function) is provided that is associated with each I/O operation. Each of the I/O requests is then submitted to a demultiplexer (Event Notification Interface). The Demultiplexer is an interface capable of handling concurrency in non-blocking input and output mode, which also helps collect requests in the form of an event and queueing up the events, resulting in an Event Queue being generated. The Reactor pattern consists of a request handler, event loop, event notification interface/demultiplexer, event queue, and resources.

Differentiate between process.nextTick() and setImmediate()

process.nextTick() and setImmediate() are two functions of the Timers module that allow the control of in executing the code in the event loop but both differ in their execution and are executed at different phases. setImmediate() takes a callback and adds it to the immediate event queue on the existing cycle of the event loop during the process.nextTick() takes a callback and not adds it to the immediate event queue but waits till the event loop is completed.

What are exit codes in Node.js.?

Exit codes in Node.js are specific codes used to finish off a process. Examples of the exit codes in Node.js are:

Internal Exception handler Run-time failure
Internal JavaScript Evaluation Failure
Uncaught fatal exception
Unused
Fatal Error

The following questions can help you in your decision-making in hiring a Nest Js developer.

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