10 Tips to Improve AngularJs Performance in 20201
Biz + Tech

10 Tips to Improve AngularJs Performance in 2020

AngularJS is an open source JavaScript framework developed and maintained by Google. It provides you with all the necessary tools which are useful to create and manage dynamic frontend web applications.

It’s very famous among developers because of its approach to web design and community support. AngularJS powers up some of the high traffic websites like Google, Virgin America, Gmail, Netflix, PayPal, and many more. 

It was created to make the process of building and managing JavaScript applications easy. It is based on the MVC model i.e. Model-View-Controller and useful for creating single page web apps. The benefit of using AngularJS is it can handle DOM and AJAX on its own rather than coding them. Additionally, it provides developers with tools to provide modular building blocks of JavaScript to mix match and test code. You can even easily add an HTML page using a simple tag.

In every programming language, there are some dos and don’ts to follow to get the most out of it. Similarly, in AngularJS as well there are some things that one must follow to enhance its performance.

Here are the top ten tips that can help you get the most!

Digest cycle:

We all know AngularJS supports two-way data binding and the digest cycle is one of the vital features which make it possible. AngularJS triggers a digest cycle when the value of the variable changes in model or view. 

The digest cycle runs automatically when the code finds a new directive. This trigger is limited to AngularJS context only. If you are trying to sync the value of a model and view out of it then it’s important to use $apply() and $digest() to sync values manually. Lastly, the digest cycle runs 2-10 times when triggered.

Digest Cycle:

Limit use of $watcher:

Whenever we use built-in Angular directives, we create watchers. For example, with the help of ng-show, you create a variable named isMine. Then there will be a watcher for this particular variable.

Watcher constantly keeps checking on this variable value until it changes.

Watchers matter a lot in the digest cycle as it keeps track of its changing value. With every watcher, there is a watcher function that runs and checks the value until all watchers stop changing their values.

Now comes a question: why does it matter?

They slow down the speed of your application. But, at the same time, it does not mean you shouldn’t use them because if you don’t then you can’t use the two-way data binding feature. It’s better to have a maximum of a hundred watch functions as it does not have lots of impact on your application.

Disable CSS:

While creating a directive in AngularJS, you can use it as an element, attribute, CSS class or comments. But, if you don’t need to use CSS class and comment directives then you can disable them for better performance. 

When CSS is enabled it takes time for images and texts to load on the website. Hence, it’s better to disable it if there is no need or less need as it helps load your website faster.

Disable debug data:

Tools like Batarang and Protractor rely on data binding and its scopes that it attaches DOM elements. Hence, it’s better to disable debugging extra data so it can help you boost your website’s performance.

Decrease use of DOM:

DOM stands for Document Object Model. It’s a programming interface used in HTML and XML documents and provides structured representation of documents. It defines ways you can access and manipulate it using scripting language.

HTML DOM looks like:

It is important to decrease the DOM usage and not use the inline style of CSS in it. Because images and heavy styles of CSS takes a lot of time to load a website. This in turn results in slow loading of the website. Hence, it’s better to use optimized images, simple styles in CSS, and make sure if any other factors apart from this are affecting website loading.

Scope Variable Tightly:

Scopes are the objects that refer to the application model and are an execution context for expressions. They are arranged in hierarchical structures similar to DOM structures. It’s important to scope all the variables tightly so that JavaScript garbage collector can free up memory fast. If memory does not free up fast then it can result in a slow, non-responsive website.

Pagination or infinite scroll:

If you want users to not go through multiple pages and show them all the content on one page, then you can use pagination or infinite scroll. In AngularJS it provides you with a directive called ngInfiniteScroll to implement this.

Let’s say your client is a small store owner and owns a website but does not need users to navigate within web pages on the website. Then with the help of this directive you can simply show them all the content on one page. As users scroll down, more content loads up for them; like news feed of any social media platform.

Use Native JavaScript or Lodash:

If you don’t know what’s Lodash then here’s a quick definition. According to edpresso Lodash is:

“Lodash is a JavaScript library that provides utility functions for common programming tasks using a functional programming paradigm; it builds upon the older underscore.js library.”

The major reason for using it while developing your application is that it makes your AngularJS development tasks easy. You can simply import all of its functions with one line.

Additionally, you can easily rewrite the main logic of your application to improve built-in methods and enhance performance. If you are not using Lodash, then you can code in native JavaScript. But, it’s a very complex and time consuming process.

Don’t use ng-repeat:

It is useful to repeat the set of HTML functions n number of times. In simple terms we can say, it works as a loop. But, it is not recommended to use ng-repeat every time as it can degrade the performance of web applications. It’s better to use its alternative, $interpolate. It renders your template for an object before converting the whole code in the DOM node and it does not affect the performance of your application.

Ng-if is better than ng-show:

ng-if removes all the elements from DOM. So, if you don’t want to show the most of the code then you can choose it. Whereas, if you want to hide some elements or show or hide CSS then ng-show is the choice.

Final words:

Today there are thousands of frameworks available in JavaScript but AngularJS remains one of the most preferable frameworks. Over the course of time, AngularJS has created its space in the programming world and it’s here to stay. 

Follow these quick tips and enhance your AngularJS performance.

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