JavaScript Optimization: Strategies & Best Practices

Practically, every website, mobile application, and web-based program depends on JavaScript. While JavaScript’s client-side scripting features can add more life and interest to programs, they also carry the risk of inefficiencies because they rely on the user’s browser and device. Consequently, it may be challenging to guarantee a consistent user experience when JavaScript is coded incorrectly.


This blog will examine the reasons behind JavaScript speed problems and offer a list of best practices for JavaScript code optimization.

Common Mistakes

As highlighted by the development team at RNF Technologies, here are inevitable mistakes that many make that cause applications to run slowly:

  • Too many scripts and libraries from third parties

As our application gets more significant, there is a good chance it will have too many Node dependencies, plugins, or even scripts, which will harm how quickly it runs. Eliminating pointless dependencies will be beneficial.

  • Lack of CDN 

Using an Information Delivery Network is an excellent approach to improve your app’s performance if it contains a lot of web content (CDN). It distributes your static material from a nearby server with a quick download rate.

  • Excessive HTTP requests

To show information, your site sends HTTP requests to a server. This implies that the longer it takes for your page to load, the more requests it produces. Your website will have a performance issue if it loads many scripts and resources. JavaScript performance is improved by delaying parsing so the browser can load other resources required for the page.

  • Avoid JavaScript code minification

Your JavaScript file can be made smaller by removing comments, shorter variable names, whitespace, and unnecessary code. Even though none of the aforementioned changes affect the app’s functionality, the smaller file size results in a quicker runtime. To do this, you can try out various minification techniques made available by RNF Technologies.

Advice For Improving The Performance Of JavaScript

Trim the HTML JavaScript 

HTML is complicated and essential for DOM object querying and modification. The DOM speed of the app might increase twofold when the HTML is decreased in half. Although it can be difficult, it is feasible to remove tags like “div” and “span.”

  • Utilize HTTP/2

The most recent HTTP protocol, HTTP/2, offers some fantastic improvements to increase JavaScript performance and speed up your site more generally. Using multiplexing, HTTP/2 enables the simultaneous transmission of several requests and answers. If you haven’t already, migrate to HTTPS as soon as possible to take advantage of HTTP/2’s performance improvements.

  • Utilize pointer references

You can also minimize DOM traversal trips by keeping pointer references for in-browser objects during instantiation. Maintaining a reference to the DOM or jQuery objects required to build your website can speed things up if you don’t anticipate your DOM changing. Alternately, you can create a local variable regarding the object if you need to iterate inside a function but haven’t stored a reference.

  • Minimizing and simplifying the coding

JavaScript performance will increase, and latency will be reduced by keeping the code small. To improve JavaScript performance, consider whether the module in question is necessary.

  1. What justifies using this framework?
  2. Does the overhead make sense?
  3. Is there a more straightforward method to complete this?

Reduce the number of open JavaScript files by combining them all into one.

  • Batch your DOM modifications

Batch up your DOM updates each time to avoid rendering the screen repeatedly. Try to update your styles at once rather than adjusting each style separately if you’re changing your style.

  • Make DOM buffers

If your DIVs are scrollable, you can utilize a buffer to remove DOM elements that aren’t currently visible from the viewport. By using this method, you may reduce memory utilization and DOM traversal.

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