The balance between the readability of the code and its optimization should be maintained at all times. You should never compromise the performance of an application over its development time. Rushing through the process for the sake of achieving faster time-to-market will make matters even more complicated.
Performance is a deciding factor in the success (or failure) of any web application. Frequent web crashes and long waiting times are annoying for visitors.
Kissmetrics found that:
- 47 percent of visitors expect a website to load in less than 2 seconds.
- 40 percent of visitors leave the website if the loading process takes more than 3 seconds.
I will tell you 9 tips that you can use to notice a multi-fold improvement in the performance of your application. Let’s get started with them.
- If a library was included by mistake and is not necessary, eliminate it as well.
Cache in the browser
Developers use scripts to provide access to a certain object. By storing such objects inside the memory of a user-defined variable, and using a variable in subsequent references to that object, you will notice an immediate improvement in performance.
Avoid memory leaks
The Java Virtual Machine (JVM) continuously analyzes an application during its lifecycle and detects objects that are not in use anymore. These objects are collected as garbage. A memory leak is a situation when the JVM is unable to recognize the unused objects, thus leading to the accumulation of garbage in the system.
During a memory leak, the loaded page will gradually occupy all of the available memory of the device and severely affect the performance.
In Chrome Dev Tools, memory leaks can be analyzed by recording a timeline in the Performance tab.
Establish well-defined environments for testing
As a developer, you need to test the applications before they go live, and testing the code requires a set of well-defined environments.
So, you should go a step further to establish well-defined testing environments, so that the application does not suffer from poor performance later on.
Users love web pages or apps that load quickly but they don’t access all the features during the initial loading process. Right?
If certain functions require user’s action for execution (e.g. clicking on an image, switching tabs, etc.), the loading of these functions can be deferred to a later time.
The delayed functionality can be loaded once the initial load of the page is complete. According to the RAIL model, Google recommends that this deferred load be done in blocks of 50ms so that the user’s interaction with the page remains unaffected.
Prioritize access to local variables
Keep in mind that you need to specify the scope and also define the function scope by preceding each variable with let or const to define the current scope. This will prevent the look-up and also speed up the code.
Use web workers to execute time-consuming codes
We come across many codes in our programming careers that take a lot of time to execute, don’t we? Running such scripts with the main thread (the UI of application) will slow down the application greatly.
Web Workers can run a script operation in a background thread and perform critical processes in a separate thread, thus ensuring that the main application is not blocked or slowed down in the process.
Save repetitive DOM items on a local variable
DOM stands for Document Object Model (DOM). It is an application programming interface (API) that defines the logical structure of documents and the way a document is accessed and manipulated.
Accessing the DOM consumes a lot of time. If you know that an element needs to be read several times, save it in a local variable.
But keep in mind: If you want to remove the value of the DOM later, the value of the variable should be set to “null” so that it does not cause any memory leak.
Make use of tools to detect issues
Lighthouse is one of the best tools to analyze the performance of web pages. It helps you to audit performance, accessibility, best practices, and SEO.
Google PageSpeed can understand a website’s performance optimizations and areas for potential improvement. The components can identify faults in a website’s compliance with Google’s Web Performance Best Practices, make adjustments automatically.
The More Tools option in Chrome can show you the memory and the CPU used by each tab. Furthermore, the ‘Performance’ view in either Firefox or Chrome can be used to analyze advanced metrics.