In a wide aspect, Node.js is a single thread process and does not expose any mode of thread management to the developer. But the thing is that the child threads in Node.js will be generated during various stages and one among the reasons is asynchronous I/O. Even though these child threads swap and run in the backdrop they do not create any blockage or hindrance in the execution of the main code.

Below mentioned are some of the considerable variations between Angular and Node.js.

Although Node.js is well suited for server-side application development, the CPU-heavy applications are not that effectively supported by  Node.js. This is because the CPU heavy applications would push the threads into critical executions and create blockages for incoming requests.

The Express JS package plays a vital role in information flow. The Express JS framework is used to control the information flow between server-side applications and routers. Advanced Node.js features such as lightweight, flexible and many other features have made it as the first choice for developing web and mobile applications.

The Just-in-time is a run time component that converts bytecode into instruction and sends it to the processor. Once you are done with the code writing part, the statements of the source language are compiled into bytecode with the help of a compiler.

Just-in-time plays a major role in Node.js. JIT improves the code execution speed to a great extent. It has the capability to convert the source code into machine code during run-time. The regularly called functions are compiled to machine code, which increases the speed of the execution process.

Below mentioned are the tasks that should be done asynchronously with the event loop.

• Heavy computation
• I/O operations
• Anything that requires blocking

The test pyramid is a diagram that explains the ratio of integration tests, unit tests, and end-to-end tests are required to write for successful completion of a project.

In Node.js the error-first callback is responsible for passing the errors and data. In Node.js the very first parameter that you are going to pass through this function must be an error object and the other parameter should be the associated data. The Error-first callback is mainly used to check if anything is wrong and handle it.  If you find no issue you can go ahead with the subsequent arguments.

The role of a module in Node.js is to combine all the relevant codes into a single unit of code that can be later presented by moving all relevant functions into a single file. Let’s consider an illustration here, for suppose you have a file called greet.js that contains two functions like below.

module.exports = {
greetInTelugu: function(){
return "NAMASKAR";
},
greetInFrench: function(){
return "SALUER";
}};

The module.exports use below code to provide two functions that can be imported into a single file.

var besantGreets = require ("./greet.js");
beasntGreets.greetInTelugu() //NAMASKAR
besantGreets.greetInFrench() //SALUER

The front end development is nothing but user interface or what a user can see and the ‘back-end’ means the application, server and database which works behind the scenes to provide information to the users.

Below mentioned are the considerable differences between front-end and back-end development.

The Major security implementations in Node.js are:

• Error Handling
• Authentications

The callback hell is widely known as a pyramid of Doom. The callback hell is a pattern that occurs due to huge nested callbacks that are unwieldy and unreadable.  It typically contains various nested callback functions it makes the code complex and hard to debug. Improper implementation of asynchronous logic is the main reason for this cause.

Chaining is a technique in which the output of a stream is tied to another stream and creates a chain of various stream operations.

Google uses V8 as a Chrome runtime engine that transforms JavaScript code into existing machine code. Besides this, it also offers various other features such as speeds up the application response & process execution and provides you with a fast running application.

Control flow is a code that has been executed between asynchronous function calls. Following are the general steps to execute control flow.

• The very first thing is to control the order of execution
• Collecting the required data
• The concurrency should be limited.
• Once you are done with the above all the next step is to invoke the program.

Syntax:

child_process.spawn(command[, args][, options])

Fork(): It is a special instance spawn() and helps in execution of new V8 engines. The core aim of this method is to allow multiple workers to run on a single Node code base for performing multiple tasks.

Syntax:

child_process.fork(modulePath[, args][, options])

The name itself resembles is global in nature and presented in every module. There is no compulsion to include them in your application, you can use them directly. The global objects are functions, modules, objects, strings etc. A few of these objects are not actually presented in the global scope but are in the module scope.

Some of the Global objects are:

• __filename
• __dirname
• Process
• Console
• Buffer, etc.

Assert in Node.js is used to write test cases. It is confined to provide feedback whenever a test case fails. This module provides you with a list of assertion tests that are used to test invariants. The assert is used internally in Node.js and you can also use it in other applications with the help of require(‘assert’) code.

The NODE_ENV variable is primarily used to flag a project when it is in the production stage. This provides clear feedback and in return, it also helps inefficient development of the projects. And the other side using NODE_ENV in production makes the application function 3 times faster.

In Node.js we have two options to read and execute files that are readFile and CreateStream.

readFile(): It needs a complete buffering process and returns response only when the entire file completes its buffering process and is read. This is a memory-intensive process and injecting a large set of data makes the process very slow.

createReadStream: it is quite the opposite of the readFile and buffers partially and considers the overall process as an event series. In this process, a file is split into chunks which are processed and sent back one by one when called. The createReadStream is highly suitable for processing the large files of data.

Node.js comes with a feature called Timer module which has multiple functions that support code execution after a specified period of time. The following are some of the various functions available under this module.

• setTimeout/clearTimeout – this function can be used to schedule the code execution after a designated amount of milliseconds time.
• setInterval/clearInterval – This function is used for executing a block of code many numbers of times.
• setImmediate/clearImmediate – this function is being employed to execute the code at the end of the present event loop cycle.
• nextTick – this function is useful to schedule a callback function that requires to be invoked in the next iteration of an event loop.

The Punycode is an encoding syntax that is being used to convert Unicode (UTF-*) string of characters into a normal ASCII string of characters. The encoding from Unicode to basic ASCII is important because the hostnames can only recognize the ASCII characters. From the release of the Node.js 0.6.2 version onwards, it has been bundled up with the  Node package. The following syntax can be helpful if you want to use it with the older versions:

Syntax:

punycode= require(‘punycode’);

The core difference between the Node.js and Ajax is that the Node.js is a server-side technology whereas Ajax is a client-side technology. To put it simply Ajax is widely used for modifying or updating the content on a webpage without having to refresh it. The Node.js server software can be used on the servers rather than web browsers.

Yes, Node.js comes with an in-built debugging client and TCP based protocol. When you want to conduct debugging to your JavaScript file, you can use the following debug argument extended with the js file name.

Syntax:

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

We have a set of Exit codes in Node.js and they serve for finishing a specific process. The global objects also included in the list of Exit codes. Following are some of the Exit codes available in Node.js

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

EventEmitter is a class of Node.js which includes multiple objects and possess the ability to emit events.  These objects contain an event emitter.on() function using which multiple functions can be tied to the named events that have emitted by the object. In case an Eventemitter object triggers an event, whatever the functions associated with that particular event are invoked synchronously.

Node.js comes with a module called Crypto which supports cryptography.  The Crypto module provides multiple cryptographic functionalities such as decipher, cypher, verify functions and sign a set of wrappers, etc.

The reason behind keeping the Express ’app’ and ‘server’ separate is because it separates the API declaration from the network-related configuration, as a result, it will be benefited in the following ways:

• You can test the API in-process without the need of network calls
• Wider code coverage metrics
• Speed up testing execution
• Cleaner and well-arranged code
• You can deploy a single API under flexible and multiple network conditions.

The console object is used to print data on stderr and stdout.