How can you avoid callbacks?

To avoid callbacks, you can use any one of the following options:

You can use modularization. It breaks callbacks into independent functions.
You can use promises.
You can use yield with Generators and Promises.

What is event-driven programming in Node.js?

In Node.js, event-driven programming means as soon as Node starts its server, it initiates its variables, declares functions and then waits for an event to occur. It is one of the reasons why Node.js is pretty fast compared to other similar technologies.

What is REPL in Node.js?

REPL stands for Read Eval Print Loop. It specifies a computer environment like a window console or Unix/Linux shell where you can enter a command, and the computer responds with an output.

REPL environment incorporates with Node.js.

What is the difference between operational and programmer errors?

Operational errors are not bugs, but create problems with the system like request timeout or hardware failure. On the other hand, programmer errors are actual bugs.

Does Node.js provide Debugger?

Yes, Node.js provides a simple TCP based protocol and built-in debugging client. For debugging your JavaScript file, you can use debug argument followed by the js file name you want to debug.

Syntax:
node debug [script.js | -e “script” |<host>:<port> :]

What is the difference between events and callbacks in Node.js?

Although, Events and Callbacks look similar the differences lies in the fact that callback functions are called when an asynchronous function returns its result whereas event handling works on the observer pattern. Whenever an event gets fired, its listener function starts executing. Node.js has multiple in-built events available through the events module and EventEmitter class which is used to bind events and event listeners.

Explain the tasks of terms used in Node REPL.

Following are the terms used in REPL with their defined tasks:

Read: It reads user’s input; parse the input into JavaScript data-structure and stores in memory.

Eval: It takes and evaluates the data structure.

Print: It is used to print the result.

Loop: It loops the above command until user press ctrl-c twice to terminate.

What is the difference between the global installation of dependencies and local installation of dependencies?

Global installation of dependencies is stored in /npm directory. While local installation of dependencies stores in the local mode. Here local mode refers to the package installation in node_modules directory lying in the folder where Node application is present.
Globally deployed packages cannot be imported using require() in Node application directly. On the other hand, locally deployed packages are accessible via require().
To install a Node project globally -g flag is used.
C:Nodejs_WorkSpace>npm install express ?g
To install a Node project locally, the syntax is:
C:Nodejs_WorkSpace>npm install express

What is a control flow function?

Control flow function is a generic piece of code that runs in between several asynchronous function calls.

What is the Punycode in Node.js?

The Punycode is an encoding syntax which is used to convert Unicode (UTF-8) string of characters to ASCII string of characters. It is bundled with Node.js v0.6.2 and later versions. If you want to use it with other Node.js versions, then use npm to install Punycode module first. You have to used require (‘Punycode’) to access it.

Syntax:
punycode = require(‘punycode’);