Node.js Interview Questions and Answers

• Go to the Nodejs.org site and download the binary files and Windows installer.
• Run the Windows installer.
• Follow the instructions on the screen for accepting the license agreement, clicking the NEXT button a few times and allowing the default settings.
• You will have to restart your computer. Remember that you may not be able to run Node.js until you restart your computer.
• Make sure you have installed Node by running simple commands just to see what version got installed.

A callback function is done at the completion of a task. This function allows other codes to be run in the meanwhile and prevent blocking. Because Node.js is an asynchronous platform, it relies heavily on the callback function. In addition, the APIs also support callbacks.

package.json is the most important file of any Node.js project and it contains the metadata of the project. It is used to give information to NPM that allows it to identify the project. It handles the project's all dependencies. It is placed on root of any project.

We can avoid callback hell by different available solutions, as mentioned below.

Promises: The promise is s result of an asynchronous operation. We can create a promise on these three states:

• Pending: When the initial state is not fulfilled or rejected.
• Fulfilled: When the operation gets completed successfully.
• Rejected: When the operation gets failed.

Generators: These are functions that can be resumed and paused. It doesn’t get executed immediately when called. Instead, it returns a generator object or generator object with which we can control the execution of the function.

Note: After learning the basics of Node, if you are looking for what more to learn, you can start with meta-programming, protocols, and much more. We have created a list of node interview questions to help them use this language to solve complex problems.

Nodemon is that tool which helps to develop application based on node.js by automatically re-initiating the application of node whenever the file changes inside the directory get detected.

It does not need any further changes to the code or the development method. Nodemon is the replacement wrapper of Node, to practice Nodemon replace the node word on the line of command at the time of executing the script

The Read Eval Print Loop (REPL) performs these four tasks - Read, Evaluate, Print and Loop. The REPL is used to execute ad-hoc Javascript functions. The REPL shell allows direct entry of javascript into a shell prompt and evaluates the results. REPL is very critical for testing, debugging, or experimenting.

Promise.all([p1, p2]).then(values => {
   console.log(values); // [7, "123"]
});

Streams are the objects that allow and enable the continuous process of reading the data from the source code and writing the data to the destination.

Streams are of four types:

• Facilitate reading operation (Readable).
• Facilitate writing operation (Writable).
• Facilitate both reading and writing operations (Duplex).
• Kind of duplex stream that performs the computations based on the available inputs (Transform).

Exit codes are the specific codes that can be used to end a process. Some of the examples of exit codes are, Uncaught Fatal Exception, Fatal Error, Non-function Internal Exception Handler, Internal Exception handler Run-Time Failure, Internal JavaScript Evaluation Failure, etc.