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10 Ways to Optimize Javascript Code | Best Tips to Follow


JavaScript Code Optimization

Javascript has won the hearts of the developers, especially the frontend developers. It has become of the best as well as popular programming languages around the world. According to SimilarTech, 24 million websites are developed using Javascript.

Javascript is a fantastic tool for frontend programming capable of providing features like interactive and feature-rich websites, and flawless web applications. Javascript can be a double-edged sword if it is not written correctly by the front end developers.

A poorly written javascript code can affect your website in several ways. Here are some of the problems that the unoptimized Javascript code cause:-

  • A considerable number of host interactions
  • Poor event handling
  • Jumbled code
  • Inefficient loops

How can I make the Javascript load faster?

The best ways to make the Javascript faster is to use the compressed files, asynchronous code, async and defer tags, cache the browsers, etc.

How to improve javascript performance?

The optimization of the javascript code plays a vital role in improving code performance. You can enhance the Javascript performance by avoiding the memory leaks, deleting the unused code, files, features, and using the compressed data.

Does Minifying JavaScript improve performance?

Yes, minified javascript improve performance to a large extent as it deletes the extra or unused functions, comments, commas, etc. So, Using the minifying javascript helps in performance improvement.

So, to avoid such issues, we will discuss the best tips to improve javascript performance:

Optimize the Javascript code by removing the unused code and features

More code in your web applications means more time; the browser will take to analyze it. Hence, it reduces the performance of the Javascript. Since all the web apps have unnecessary features and code in the development environment, here is the dire need for a Javascript code optimizer.

The javascript code optimization tools that can be used are Google Closure Compiler and Uglify JS. These js code optimization tools delete the unused commas, comments, etc., and remove the “dead code.” Here is an example of code optimization.

Before Optimization


After Optimization


Cache it to boost the Javascript code performance

You can enhance the speed and performance of the Javascript code by reducing latency and network traffic. The Javascript code caching can be done through two techniques – Javascript cache API by service worker installation and HTTP protocol cache. Caching is necessary not only in the Javascript code but also in the frontend frameworks.

Eliminate the problem of Memory leaks

There is no doubt that garbage collection is performed automatically in Javascript, but it doesn’t you can ignore the memory section. So, here frontend developers can use the function like WeakMap and WeakSet to tackle the problem of memory leaks.

The javascript performance tools that can be used to avoid the memory leaks problem is Chrome Dev Tools.

Avoid unwanted iterations by breaking the loops as soon as possible

No matter how large or small the cycle of a loop, it always consumes a significant amount of time to load. So, it is recommended for you to break the large loops as soon as possible. It can be achieved by using the two keywords like break and continue. For instance, you would not use the break keyword; then, this loop will run 10000 times.

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Reduce DOM interactions

The several interactions with the DOM in Javascript results in the problem of lagging and unpredictability. Since, whenever you access the DOM, it always refreshes the browser. So, the only solution is to reduce the number of DOM interactions.

Try to access the DOM only once and use it as a local variable. You can remove the value by setting it to null. As a result, the garbage collection process will occur, and it will eliminate the problem of memory leaks.

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Use HTTP/2 Protocol

HTTP/2 is the latest and advanced version of the HTTP protocol. It provides an immense number of benefits by improving the Javascript code performance, and it also enhances the speed of the website.

HTTP/2 allows multiple requests and responses at the same time. So, it helps to speed up javascript load time.

You can check the difference between these two protocols by visiting this website: HTTP vs HTTPS

Prevent thread blocking with the use of Asynchronous code

As we all know, Javascript is synchronous by default and is single-threaded. It means it blocks or prevents the other code statements until the current code is running. So, Javascript is single-threaded. But we can tackle this situation by using asynchronous code. So, use the Asynchronous API in Javascript code for optimization.

Use of Async and Defer Tags for Asynchronous loading of Javascript

You can add the Async tag to the Javascript code to not interrupt the DOM model while loading or executing.

Use the Async tag so that browser loads the script without affecting the rendering process. However, the Defer tag can be used when you want to tell the browser to load the script after the rendering process finished.

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Read More: How to Defer Parsing of JavaScript in WordPress?

Increase the Javascript performance by compressing the files

Do you know? Compressions can reduce the size of your file by 80%. The minification process shrinks the file size to reduce the page load time. You can use the method of the Gzip method for the compression of files. Since the use of a small-sized file would increase the Javascript performance by ten times.

Order is necessary for the element loading

Last but not least tip for Javascript code optimization is to organize the element during the loading process. It is essential to know that all the elements in the <head> section are pre-loaded, so it displays on-screen before the visitor sees anything on the browser. So, the order is necessary. Since the unordered or unorganized page always shows a white page to the visitor. So, arrange all the elements in a logical way. It will not only enhance performance but also helps to increase user engagement.

In a few words

Although javascript has become the number one choice of developers, it still requires some tips and tricks to perform better. I hope all these hacks help you to have a high-performance javascript. If you are looking for further assistance or boosting the performance, you can hire the developers of Tekki Web Solutions Pvt. Ltd.


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