5 Common Mistakes to Avoid When Building a Node.js Application

This article will discuss some common mistakes that Node.js developers often make in Node.js development. While Node.js has a set of rules for writing secure code, no platform is entirely immune to vulnerabilities. 

What is Nodejs?

Node.js is one of the most prevalent runtime environments for its faster execution of JavaScript programs. It is an open-source and cross-platform technology, utilizing Chrome’s V8 JavaScript engine to run JavaScript code independent of web browsers. As a runtime environment, Node.js provides critical functionalities for faster program execution. Its speed and performance make it a popular choice for running JavaScript applications.

Let’s look at a few typical errors developers often make during development.

1. Blocking the event loop

Node.js runs JavaScript code in a single-threaded manner, implying that processes occur in a sequence (one by one). This approach minimizes resource consumption. However, Node.js utilizes an asynchronous technique to enable the execution of other commands without blocking the main event. As a result, you can run the program without compromising performance and giving much load to the system. 

But if you run CPU-intensive tasks in Node.js while thousands of clients are connected simultaneously, it can cause an event block, forcing connected clients to wait. As a result, the application’s performance may suffer.

CPU-intensive tasks could be such as sorting a large array. If you want to run such a task, it is essential to check if there are not many users connected at that time, as it could impact the performance. 

Let’s understand this with this example; 

In this example, we have run a function to sort an array. 

function sortUsersByAge(users) {

users.sort(function(a, b) {

return a.age < b.age ? -1 : 1

 })

}

In case it is for a small array, it will be fine. But if it were for a large array, it would negatively impact overall performance. In such a case, you could employ an external worker to avoid hogging the event loop. 

2. Invoking more than once

A callback is a function that is passed as an kayaşehir escort argument to another function, often used in asynchronous programming when a function is called but not returned instantly.

Callbacks are used extensively in Node.js, and APIs are built around callbacks.

Let’s understand this with the following example; 

function test() {

  console.log("Begin");

  for (var i = 0; i < 3; i++) {

    setTimeout(function() {

      console.log("Hello, world!");

    }, i * 1000);

  }

  console.log("Waiting...");

}

test();

In this example, the test function calls the setTimeout function three times, passing in a different delay each time. The setTimeout function schedules the callback function to be called after the specified number of milliseconds. The callback function, in this case, simply logs the message “Hello, world!”

The problem with this code is that the callback function is called three times, even though it only needs to be called once. This can be fixed by using a promise.

Here is an example of how you could have write it differently to avoid callback multiple times:

function test() {

  console.log("Begin");

  return new Promise((resolve, reject) => {

    for (var i = 0; i < 3; i++) {

      setTimeout(() => {

        resolve("Hello, world!");

      }, i * 1000);

    }

  });

}

test().then(console.log);

In this example, the test function returns a promise. The promise is resolved when the callback function is called. The then method is used to attach a callback function to the promise. The callback function is called when the promise is resolved. The callback function does nothing more than record the phrase “Hello, world!” to the console.

By using a promise, we can ensure that the callback function is only called once, even though it is scheduled to be called multiple times. This improves the efficiency and readability of the code.

3. Nested callbacks

While nested callbacks are fine, deeply nested callbacks, often called “callback hell,” can lead to an uncontrollable code loop.

The more complex the task, the worst callback hell can be seen. Look at the following example; 

function getData(URL, callback) {

  // Make an asynchronous request to the given URL

  fetch(URL)

    .then(response => response.json())

    .then(data => callback(data));

       }

getData('https://example.com/api/users', function(users) {

  // Do something with the users

});

In this example, the getData function takes two arguments: a URL and a callback function. The getData function makes an asynchronous request to the given URL and then calls the callback function with the results when the request has been completed.

The problem with this code is that the getData function is nested within the callback function for the fetch function. This can make the code difficult to read and maintain, especially if there are a large number of callbacks nested within each other.

There are a number of ways to avoid callback hell. One way is to use promises. Promises are a more concise and easier-to-read way of representing asynchronous operations.

Another way to avoid callback hell is to use asynchronous programming patterns, such as generators.

Here is an example of how to use promises to avoid callback hell:

function getData(url) {

  return new Promise((resolve, reject) => {

    // Make an asynchronous request to the given URL

    fetch(URL)

      .then(response => response.json())

      .then(data => resolve(data))

      .catch(error => reject(error));

   });

}

getData('https://example.com/api/users')

  .then(users => {

    // Do something with the users

  });

4. Callbacks to run synchronously

While the concept of callbacks being asynchronous is easy to understand for developers, it is still important to explain why this is the case and its significance in programming.

The concept of asynchronous callbacks is not unique; it remains highly popular. In JavaScript, a callback with a specific purpose may not execute until the associated task is completed. This enables the current function to continue executing without getting stuck in the middle.

Let’s understand with the following example; 

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

It will give output first print is begin then it will print waiting …. followed by Done!. 

5. Not Using Supervisor Programs

Even if you are running a program in a local environment, it is recommended to use supervisor programs. Developers widely praise them for handling errors efficiently and triggering automated restarts. Developers can benefit from the feature they offer, such as error handling, automatic application restart, etc. This practice offers convenience and helps ensure that the program continues running smoothly.

Using a supervisor program thus brings forth numerous advantages for developers. They can be an effective option in application development, from debugging to program stopping and restarting the program when required.

Conclusion

This article outlines the common mistakes to avoid during node js development. Despite following standard practices and guidelines advised by experts, coding is intrinsically prone to errors. It is vital to educate yourself with these practices and procedures to minimize the chance of errors. 

Nevertheless, it is essential to acknowledge that errors can still arise and are difficult to avoid entirely, and in case you are not able to solve the problem in your app, you consider taking assistance from Node js consulting services. 

These professionals have in-depth knowledge and experience in resolving issues and offering guidance on developing Node.js applications. Whether you need resources, suggestions, or solutions, Node.js consulting can provide prompt assistance and help you navigate any difficulties.

Are you searching for a Node js development company that can help you build a high-performing application using a modern tech stack — Nodejs? We excel in developing high-performing apps and have served many clients globally. 

With our Node js development service, we can also help you migrate your existing applications to Node.js for improved performance and productivity. 

Let’s connect with us today, and you will get the best and most dedicated node js developers for your project.