Top Mistakes That Node.js Developers Make and Should be Avoided

In this article, we will take a look at some common mistakes that developers new to Node.js often make, and how they can be avoided to become a Node.js pro.

For the past few years, Node.js, accounting for its growth and popularity, has been a talking point for some time now. Well-establish companies like **Walmart and PayPal **have adapted it, making it one of the most recognized languages at present. However, as many other platforms, Node.js faces a lot of development problems that includes crucial mistakes committed by the developers themselves.

However, like any other platform, Node.js is vulnerable to developer problems and issues. Some of these mistakes degrade performance, while others make Node.js appear straight out unusable for whatever you are trying to achieve. In this article, we will take a look at ten common mistakes that developers new to Node.js often make, and how they can be avoided to become a Node.js pro.

1. Blocking the event loop

Being a single-threaded environment, no two parts of your application can run in parallel. Simply put, since Node.js runs on a single thread, anything which blocks the event loop, blocks everything. Here, concurrency is achieved by handling input-output operations asynchronously. For example, what allows Node.js to focus on some other part of the application is a request to the database engine, from Node.js to fetch some document. However, all it takes to block the event loop is a piece of CPU-bound code in a Node.js instance with many clients connected, making all the clients wait. There is no clear-cut solution to this problem, other than to address each case individually. The primary idea is to not do CPU intensive work within the front facing Node.js instances, the ones clients connect to concurrently.

2. Nested Callback or Callback Hell

If you properly analyze the common issues with Node.js, you would know that most of the problems are associated with callbacks and the callback hell or nested callback, whatever you may term it is one of the general mistakes.

In fact, this particular problem persists in most of the application development programs. The concern usually originates because the development of the application is a complex process. It also becomes difficult to maintain the codes.But you can sort out this issue by writing simple functions that are easy to read and providing them suitable links. For instance, codes such as Generators, Promises etc. will be helpful and you can keep the codes error free.The developers who expect that the call back will operate serially shouldn’t get under this misconception as everything is not carried out synchronously. Therefore, it is suggested that the addition must be done instantly after the call back to ensure everything goes smoothly.

3. Expecting Callbacks to Run Synchronously

Asynchronous programming with callbacks may not be something unique to JavaScript and Node.js, but they are responsible for its popularity. With other programming languages, we are accustomed to the predictable order of execution where two statements will execute one after another, unless there is a specific instruction to jump between statements. Even then, these are often limited to conditional statements, loop statements, and function invocations.

However, in JavaScript, with callbacks a particular function may not run well until the task it is waiting on is finished. The execution of the current function will run until the end without any stop:

function testTimeout() {
	console.log(“Begin”)
	setTimeout(function() {
		console.log(“Done!”)
	}, duration * 1000)
	console.log(“Waiting..”)
}

As you will notice, calling the “testTimeout” function will first print “Begin”, then print “Waiting…” followed by the the message “Done!” after about a second.

Anything that needs to happen after a callback has fired needs to be invoked from within it.

4. Lack of Profiling and Zero Monitoring

Often confused for testing, profiling is a completely different process. Profiling information helps with program optimization by studying various aspects related to the program like its space or function return time.In Node.js applications, profiling will help you understand things like delay in the event loop, system load, and CPU load or memory usage.

5. Developer is Unknown to Developing Tools

Often it is seen that in case the developers are inexperienced and fresher into the application development field, he remains unknown to the developing tools. It has already been indicated earlier that Node.js helps in complicated application building and if the developer is not familiar with the basic modules he may face problems.

The developer should know that if any change is done at the source, he has to restart and also he needs to refresh the browser when the static codes are getting modified and affecting the performance of the application. For restarting the server, you can use modules such as nodemon and for refreshing the nodemon and livereload is regarded appropriate.

6. Invoking a Callback More Than Once

JavaScript has relied on callbacks since forever. In web browsers, events are handled by passing references to (often anonymous) functions that act like callbacks. In Node.js, callbacks used to be the only way asynchronous elements of your code communicated with each other - up until promises were introduced. Callbacks are still in use, and package developers still design their APIs around callbacks. One common Node.js issue related to using callbacks is calling them more than once. Typically, a function provided by a package to do something asynchronously is designed to expect a function as its last argument, which is called when the asynchronous task has been completed:

module.exports.verifyPassword = function(user, password, done) {
	if(typeof password !== ‘string’) {
		done(new Error(‘password should be a string’))
		return
	}

	computeHash(password, user.passwordHashOpts, function(err, hash) {
		if(err) {
			done(err)
			return
		}

		done(null, hash === user.passwordHash)
	})
}

Notice how there is a return statement every time “done” is called, up until the very last time. This is because calling the callback doesn’t automatically end the execution of the current function. If the first “return” was commented out, passing a non-string password to this function will still result in “computeHash” being called. Depending on how “computeHash” deals with such a scenario, “done” may be called multiple times. Anyone using this function from elsewhere may be caught completely off guard when the callback they pass is invoked multiple times.

Being careful is all it takes to avoid this Node.js error. Some Node.js developers adopt a habit of adding a return keyword before every callback invocation:

if(err) {
	return done(err)
}

In many asynchronous functions, the return value has almost no significance, so this approach often makes it easy to avoid such a problem.

7. Assigning to “exports”, Instead of “module.exports”

Node.js treats each file as a small isolated module. If your package has two files, perhaps “a.js” and “b.js”, then for “b.js” to access “a.js”’s functionality, “a.js” must export it by adding properties to the exports object:

// a.js
exports.verifyPassword = function(user, password, done) { ... }

When this is done, anyone requiring “a.js” will be given an object with the property function “verifyPassword”:

// b.js
require(‘a.js’) // { verifyPassword: function(user, password, done) { ... } } 

However, what if we want to export this function directly, and not as the property of some object? We can overwrite exports to do this, but we must not treat it as a global variable then:

// a.js
module.exports = function(user, password, done) { ... }

Notice how we are treating “exports” as a property of the module object. The distinction here between “module.exports” and “exports” is very important, and is often a cause of frustration among new Node.js developers.

8. Throwing Errors from Inside Callbacks

JavaScript has the notion of exceptions. Mimicking the syntax of almost all traditional languages with exception handling support, such as Java and C++, JavaScript can “throw” and catch exceptions in try-catch blocks:

function slugifyUsername(username) {
	if(typeof username === ‘string’) {
		throw new TypeError(‘expected a string username, got '+(typeof username))
	}
	// ...
}

try {
	var usernameSlug = slugifyUsername(username)
} catch(e) {
	console.log(‘Oh no!’)
}

However, try-catch will not behave as you might expect it to in asynchronous situations. For example, if you wanted to protect a large chunk of code with lots of asynchronous activity with one big try-catch block, it wouldn’t necessarily work:

try {
	db.User.get(userId, function(err, user) {
		if(err) {
			throw err
		}
		// ...
		usernameSlug = slugifyUsername(user.username)
		// ...
	})
} catch(e) {
	console.log(‘Oh no!’)
}

If the callback to “db.User.get” fired asynchronously, the scope containing the try-catch block would have long gone out of context for it to still be able to catch those errors thrown from inside the callback.

This is how errors are handled in a different way in Node.js, and that makes it essential to follow the (err, …) pattern on all callback function arguments - the first argument of all callbacks is expected to be an error if one happens.

9. Assuming Number to Be an Integer Datatype

Numbers in JavaScript are floating points - there is no integer data type. You wouldn’t expect this to be a problem, as numbers large enough to stress the limits of float are not encountered often. That is exactly when mistakes related to this happen. Since floating point numbers can only hold integer representations up to a certain value, exceeding that value in any calculation will immediately start messing it up. As strange as it may seem, the following evaluates to true in Node.js:

Math.pow(2, 53)+1 === Math.pow(2, 53)

Unfortunately, the quirks with numbers in JavaScript doesn’t end here. Even though Numbers are floating points, operators that work on integer data types work here as well:

5 % 2 === 1 // true
5 >> 1 === 2 // true

However, unlike arithmetic operators, bitwise operators and shift operators work only on the trailing 32 bits of such large “integer” numbers. For example, trying to shift “Math.pow(2, 53)” by 1 will always evaluate to 0. Trying to do a bitwise-or of 1 with that same large number will evaluate to 1.

Math.pow(2, 53) / 2 === Math.pow(2, 52) // true
Math.pow(2, 53) >> 1 === 0 // true
Math.pow(2, 53) | 1 === 1 // true

You may rarely need to deal with large numbers, but if you do, there are plenty of big integer libraries that implement the important mathematical operations on large precision numbers, such as node-bigint.

10. Ignoring the Advantages of Streaming APIs

Let’s say we want to build a small proxy-like web server that serves responses to requests by fetching the content from another web server. As an example, we shall build a small web server that serves Gravatar images:

var http = require('http')
var crypto = require('crypto')

http.createServer()
.on('request', function(req, res) {
	var email = req.url.substr(req.url.lastIndexOf('/')+1)
	if(!email) {
		res.writeHead(404)
		return res.end()
	}

	var buf = new Buffer(1024*1024)
	http.get('http://www.gravatar.com/avatar/'+crypto.createHash('md5').update(email).digest('hex'), function(resp) {
		var size = 0
		resp.on('data', function(chunk) {
			chunk.copy(buf, size)
			size += chunk.length
		})
		.on('end', function() {
			res.write(buf.slice(0, size))
			res.end()
		})
	})
})
.listen(8080)

In this particular example of a Node.js problem, we are fetching the image from Gravatar, reading it into a Buffer, and then responding to the request. This isn’t such a bad thing to do, given that Gravatar images are not too large. However, imagine if the size of the contents we are proxying were thousands of megabytes in size. A much better approach would have been this:

http.createServer()
.on('request', function(req, res) {
	var email = req.url.substr(req.url.lastIndexOf('/')+1)
	if(!email) {
		res.writeHead(404)
		return res.end()
	}

	http.get('http://www.gravatar.com/avatar/'+crypto.createHash('md5').update(email).digest('hex'), function(resp) {
		resp.pipe(res)
	})
})
.listen(8080)

Here, we fetch the image and simply pipe the response to the client. At no point do we need to read the entire content into a buffer before serving it.

11. Using Console.log for Debugging Purposes

In Node.js, “console.log” allows you to print almost anything to the console. Pass an object to it and it will print it as a JavaScript object literal. It accepts any arbitrary number of arguments and prints them all neatly space-separated. There are a number of reasons why a developer may feel tempted to use this to debug his code; however, it is strongly recommended that you avoid “console.log” in real code. You should avoid writing “console.log” all over the code to debug it and then commenting them out when they are no longer needed. Instead, use one of the amazing libraries that are built just for this, such as debug.

Packages like these provide convenient ways of enabling and disabling certain debug lines when you start the application. For example, with debug it is possible to prevent any debug lines from being printed to the terminal by not setting the DEBUG environment variable. Using it is simple:

// app.js
var debug = require(‘debug’)(‘app’)
debug(’Hello, %s!’, ‘world’)

To enable debug lines, simply run this code with the environment variable DEBUG set to “app” or “*”:

DEBUG=app node app.js

12. Not Using Supervisor Programs

Regardless of whether your Node.js code is running in production or in your local development environment, a supervisor program monitor that can orchestrate your program is an extremely useful thing to have. One practice often recommended by developers designing and implementing modern applications recommends that your code should fail fast. If an unexpected error occurs, do not try to handle it, rather let your program crash and have a supervisor restart it in a few seconds. The benefits of supervisor programs are not just limited to restarting crashed programs. These tools allow you to restart the program on crash, as well as restart them when some files change. This makes developing Node.js programs a much more pleasant experience.

There is a plethora of supervisor programs available for Node.js. For example:

• pm2
• forever
• nodemon
• supervisor

All these tools come with their pros and cons. Some of them are good for handling multiple applications on the same machine, while others are better at log management. However, if you want to get started with such a program, all of these are fair choices.

#node-js #javascript #web-development

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Hire Dedicated Node.js Developers - Hire Node.js Developers

If you look at the backend technology used by today’s most popular apps there is one thing you would find common among them and that is the use of NodeJS Framework. Yes, the NodeJS framework is that effective and successful.

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WebClues Infotech offers different levels of experienced and expert professionals for your app development needs. So hire a dedicated NodeJS developer from WebClues Infotech with your experience requirement and expertise.

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Why use Node.js for Web Development? Benefits and Examples of Apps

Front-end web development has been overwhelmed by JavaScript highlights for quite a long time. Google, Facebook, Wikipedia, and most of all online pages use JS for customer side activities. As of late, it additionally made a shift to cross-platform mobile development as a main technology in React Native, Nativescript, Apache Cordova, and other crossover devices. 

Throughout the most recent couple of years, Node.js moved to backend development as well. Designers need to utilize a similar tech stack for the whole web project without learning another language for server-side development. Node.js is a device that adjusts JS usefulness and syntax to the backend. 

What is Node.js? 

Node.js isn’t a language, or library, or system. It’s a runtime situation: commonly JavaScript needs a program to work, however Node.js makes appropriate settings for JS to run outside of the program. It’s based on a JavaScript V8 motor that can run in Chrome, different programs, or independently. 

The extent of V8 is to change JS program situated code into machine code — so JS turns into a broadly useful language and can be perceived by servers. This is one of the advantages of utilizing Node.js in web application development: it expands the usefulness of JavaScript, permitting designers to coordinate the language with APIs, different languages, and outside libraries.

What Are the Advantages of Node.js Web Application Development? 

Of late, organizations have been effectively changing from their backend tech stacks to Node.js. LinkedIn picked Node.js over Ruby on Rails since it took care of expanding responsibility better and decreased the quantity of servers by multiple times. PayPal and Netflix did something comparative, just they had a goal to change their design to microservices. We should investigate the motivations to pick Node.JS for web application development and when we are planning to hire node js developers. 

Amazing Tech Stack for Web Development 

The principal thing that makes Node.js a go-to environment for web development is its JavaScript legacy. It’s the most well known language right now with a great many free devices and a functioning local area. Node.js, because of its association with JS, immediately rose in ubiquity — presently it has in excess of 368 million downloads and a great many free tools in the bundle module. 

Alongside prevalence, Node.js additionally acquired the fundamental JS benefits: 

• quick execution and information preparing; 
• exceptionally reusable code; 
• the code is not difficult to learn, compose, read, and keep up; 
• tremendous asset library, a huge number of free aides, and a functioning local area. 

In addition, it’s a piece of a well known MEAN tech stack (the blend of MongoDB, Express.js, Angular, and Node.js — four tools that handle all vital parts of web application development). 

Designers Can Utilize JavaScript for the Whole Undertaking 

This is perhaps the most clear advantage of Node.js web application development. JavaScript is an unquestionable requirement for web development. Regardless of whether you construct a multi-page or single-page application, you need to know JS well. On the off chance that you are now OK with JavaScript, learning Node.js won’t be an issue. Grammar, fundamental usefulness, primary standards — every one of these things are comparable. 

In the event that you have JS designers in your group, it will be simpler for them to learn JS-based Node than a totally new dialect. What’s more, the front-end and back-end codebase will be basically the same, simple to peruse, and keep up — in light of the fact that they are both JS-based. 

A Quick Environment for Microservice Development 

There’s another motivation behind why Node.js got famous so rapidly. The environment suits well the idea of microservice development (spilling stone monument usefulness into handfuls or many more modest administrations). 

Microservices need to speak with one another rapidly — and Node.js is probably the quickest device in information handling. Among the fundamental Node.js benefits for programming development are its non-obstructing algorithms.

Node.js measures a few demands all at once without trusting that the first will be concluded. Many microservices can send messages to one another, and they will be gotten and addressed all the while. 

Versatile Web Application Development 

Node.js was worked in view of adaptability — its name really says it. The environment permits numerous hubs to run all the while and speak with one another. Here’s the reason Node.js adaptability is better than other web backend development arrangements. 

Node.js has a module that is liable for load adjusting for each running CPU center. This is one of numerous Node.js module benefits: you can run various hubs all at once, and the environment will naturally adjust the responsibility. 

Node.js permits even apportioning: you can part your application into various situations. You show various forms of the application to different clients, in light of their age, interests, area, language, and so on. This builds personalization and diminishes responsibility. Hub accomplishes this with kid measures — tasks that rapidly speak with one another and share a similar root. 

What’s more, Node’s non-hindering solicitation handling framework adds to fast, letting applications measure a great many solicitations. 

Control Stream Highlights

Numerous designers consider nonconcurrent to be one of the two impediments and benefits of Node.js web application development. In Node, at whatever point the capacity is executed, the code consequently sends a callback. As the quantity of capacities develops, so does the number of callbacks — and you end up in a circumstance known as the callback damnation. 

In any case, Node.js offers an exit plan. You can utilize systems that will plan capacities and sort through callbacks. Systems will associate comparable capacities consequently — so you can track down an essential component via search or in an envelope. At that point, there’s no compelling reason to look through callbacks.

 

Final Words

So, these are some of the top benefits of Nodejs in web application development. This is how Nodejs is contributing a lot to the field of web application development. 

I hope now you are totally aware of the whole process of how Nodejs is really important for your web project. If you are looking to hire a node js development company in India then I would suggest that you take a little consultancy too whenever you call. 

Good Luck!

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Top 10 NodeJs app Development Companies- ValueCoders

Node.js is a prominent tech trend in the space of web and mobile application development. It has been proven very efficient and useful for a variety of application development. Thus, all business owners are eager to leverage this technology for creating their applications.

Are you striving to develop an application using Node.js? But can’t decide which company to hire for NodeJS app development? Well! Don’t stress over it, as the following list of NodeJS app development companies is going to help you find the best partner.

Let’s take a glance at top NodeJS application development companies to hire developers in 2021 for developing a mind-blowing application solution.

Before enlisting companies, I would like to say that every company has a foundation on which they thrive. Their end goals, qualities, and excellence define their competence. Thus, I prepared this list by considering a number of aspects. While making this list, I have considered the following aspects:

• Review and rating
• Enlisted by software peer & forums
• Hourly price
• Offered services
• Year of experience (Average 8+ years)
• Credibility & Excellence
• Served clients and more

I believe this list will help you out in choosing the best NodeJS service provider company. So, now let’s explore the top NodeJS developer companies to choose from in 2021.

#1. JSGuru

JSGuru is a top-rated NodeJS app development company with an innovative team of dedicated NodeJS developers engaged in catering best-class UI/UX design, software products, and AWS professional services.

It is a team of one of the most talented developers to hire for all types of innovative solution development, including social media, dating, enterprise, and business-oriented solutions. The company has worked for years with a number of startups and launched a variety of products by collaborating with big-name corporations like T-systems.

If you want to hire NodeJS developers to secure an outstanding application, I would definitely suggest them. They serve in the area of eLearning, FinTech, eCommerce, Telecommunications, Mobile Device Management, and more.

• Ratings: 4.9/5.0

• Founded: 2006

• Headquarters: Banja Luka, Bosnia, and Herzegovina

• Price: Starting from $50/hour

Visit Website - https://www.valuecoders.com/blog/technology-and-apps/top-node-js-app-development-companies

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Node JS Development Company | Hire Node.js Developers

The NineHertz promises to develop a pro-active and easy solution for your enterprise. It has reached the heights in Node js web development and is considered as one of the top-notch Node js development company across the globe.

The NineHertz aims to design a best Node js development solution to improve their branding status and business profit.

Looking to hire the leading Node js development company?

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10 Reasons Which Make Node.js "A First Choice For Web-App Development"

Businesses and developers opt for Node.js since it possesses unbeatable features like JavaScript. 43% of Node.js developers utilize it for business apps, and 85% primarily use it for web application development. So It Has More To Offer Than Thought!

Before we go ahead, it is essential to understand why Node.js is better?

The Open- source and cross-platform attributes of Node.js make this a preferred choice for web development. Nonetheless, enterprises would be wondering about possible alternatives to Node.js. So here, throughout this blog, we’ll highlight critical pointers that’ll make Node.js a real success for web app development.

Read Full Blog- https://vocal.media/stories/title-10-reasons-which-make-node-js-a-first-choice-for-web-app-development

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