Tips to Improve JavaScript Performance

dotsemi profile image Rohan Singh ・7 min read

Tips to improve JavaScript Performance


JavaScript is one of the most prominent and efficient languages that is being used to develop websites or applications. It is used everywhere, from games to education, and websites to operating systems. Despite the roster of features, Javascript development companies still find traditional JS to be lacking in many aspects. Some of them have been are mentioned below:

● Performance is affected when heavy computer tasks are handled.
● Due to its unstable API, it invites a lot of code changes.
● Asynchronous programming mode, because of the async API.
● Lack of library support
● Developers have less experience

These are a few of the problems that may cause dome interruption in the performance of JavaScript. It is very easy to overcome these issues. In this article, you will know the tips to improve JavaScript’s performance for your software or application. The tips are given below:

1. Reduce Computational Complexity

If you are writing complex code, you must use algorithms to reduce computational complexity. This will help you in numerous ways. First thing is that you will get the same results that you were getting by spending a lot of time without any pre-planned algorithm, and that too with less effort. It will also help to revert recursive calls.

It will help you to remember all the repeated functions without any confusion, be it calculations, calls, or variables. You must also use bit-level operators and replace certain operations that can be replaced as they take less processor cycle. This will reduce the time taken by the code to get executed and also reduces the chances of any run-time errors.

Another thing that you can do to reduce the complexity of your code is to use search arrays to find a value that depends on some other value instead of using case statements or switches. This will also simplify all the mathematical formulas and functions that you have to apply. While hiring javascript developers, you must test their knowledge for performance handling in complex processes. This can ensure a powerful app with robust performance.

2. Use Tools To Detect Problems

For performance-boosting, there are multiple tools you can opt for. One of such tools for efficient JavaScript development services is Lighthouse, which is popularly used to detect and solve performance issues. It helps to detect and solve problems such as accessibility, audit performance, and SEO. Just like Lighthouse, Google’s PageSpeed also helps to detect the areas that need improvement and that too very quickly.

It also helps in the performance optimization of a website. Similarly, the Devtools performance analysis also helps in detecting such problems and optimizing the overall performance of a website. It helps you to simulate networks, CPU consumption, etc. while the page is loading. You won’t even know about the problems and they will be fixed within seconds.

3. Detect Memory Leaks

The most notorious and common annoying problems for Web development services is a memory leak. When memory leaks, your page will start to take more and more memory each time, and eventually it will take up the whole memory of your device. This memory leak can occur due to the removal of DOM pieces from the page. Such issues can be detected by the use of memory leak detection tools. Chrome Dev Tools is one of the most popular tools.

4. Take Off The Unnecessary Load

It is a very simple phenomenon where if you put an excessive load on something, it will eventually break, and the same goes for JavaScript. If a JavaScript development company does not take care of this issue, it might face a lot of performance-based problems with the webs apps. For example, if a user is loading a page and it is taking some time then the user generally clicks a lot of buttons and opens other tabs as well. This will only make the situation worse and the JavaScript code can take more time to load than expected.

5. Don’t Use Too Much Memory

If you fill the memory of any system up to the brim, its functioning will be affected. A JavaScript developer must know how to refrain from using too much memory while providing web development services. The problem becomes worse with the improper and inefficient use of JS.

It is difficult to determine how much memory a website or an application will take up but if somehow the code demands more memory the garbage collector will be executed and the page or application will slow down. Hence, the use of memory is inversely proportional to the performance of the application or website developed by JavaScript. If memory increases, the performance will decrease.

6. Delete Unused JavaScript

The codes that are taking up space and are not of any use should be deleted immediately. This will improve the time taken by the browser to compile the code. All the front-end development service providers must emphasize the importance of clean code. This will help a lot in improving the functionality of your system by reducing the load time of the website and improving the user experience.

7. Specify Execution Context

Before even starting to make the project, JavaScript development services providers pre-plan the environment for the execution of the project. It is a very important step. This will help you to test the code and look for any kind of improvement. You should never test your code in a single environment as it can give biased results. Hence, it is very important to set up a specific environment.

8. Keep Codes Light And Small

Putting the point again in a note, front end development service providers must keep the code small and light for the faster execution of the app. You need to keep your code light and small as much as possible. The compact code will allow you to save your time to type the code and will also reduce the chances of any kind of error due to excessive typing.

For this, you have to pre-plan things. You need to make algorithms repeatedly until you find the shortest and simplest way. It is better to spend time improving your algorithm than to write complex codes and then find all the errors in it.

9. Cache Memory In The Browser

To implement this there are two ways: first is by using JavaScript cache API which is only done by installing the service worker. The second is by using the Hypertext Transmission Protocols (HTTP) protocols cache. In order to attain speed or performance, the scripts are majorly used to access the object. Repeatedly storing the object inside the user-defined variables as well as using the variables in reference to that object results in an increase in the speed.

10. Use Of Web Worker When Execution Of Code Requires A Lot Of Time

As per the Mozilla Developers Network (MDN), web workers allow executing scripts and certain operations in the background, keeping it separate from the main execution thread of web applications. Basically, the web worker makes complex calculations flexible that does not result in blocking of the user’s interface thread. Web workers allow generating new threads for efficient performance. This way, the tasks that are running and blocking other tasks are passed on to web workers so that the main thread can run without getting blocked.

11. Prioritize The Local Variables

JavaScript first finds the variables that exist locally and then searches the upper level of scope until global variables. So the use of local variables or saving these variables allows JavaScript to access faster. These local variables are declared for short-time purposes with a specific scope.

Local variables are only for the specific scope which is passed to the multilevel scope. While defining the function the scope of the variable should be under function scope and without preceding the declaration of variables, the declaration of variables with the keyword “constant” or let in order to interpret the current scope so as to increase the speed of code.

12. Reduce the Use of Global Variables

As local variables get destroyed by the end of the function or the specific scope after proper execution. On the other hand, the local variables do not affect the other function code. Whereas the practice of global variables will harm the performance. As global variables exist even after the execution of functions code, it may change or alter the definition of variables, etc.

So without any global variables, the lifetime of the script would increase and also enhance the performance of the code. Global variables only get destroyed when the execution of the whole program ends, otherwise, they do not. So using global variables is a bad practice.

13. Avoid Unwanted Loops

It is no secret that while writing code, it is easier to work with the loop. It makes your code easy but it can put a lot of stress on the browser. Running each iteration can take a lot of time and space. This can make your website or application very slow and directly affect its performance. Instead of using loops, you can use other alternatives such as storing the values in an array instead of running each iteration. This will make your work easy as well as will be healthy for your browser.


JavaScript has a few drawbacks but you can overcome all of them with the help of the above-mentioned tips to improve its performance. This will make your application or website work smoothly and will enhance its user experience. It might be difficult for you to implement all of these tips in a single project, but with time, you will be able to do it. It is better to hire a javascript developer, instead of trying hands on everything and end up with messed up code.


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