angular performance optimization

Angular is structured so that you can build even a single-page application, a medium-sized app, or even a large-scale app. It has a strong foundation that can handle the demands of complex programs with ease. But heavy programs might lag because of poor performance optimization. Discover more about angular performance optimization that will help to improvise the app’s performance.

The numerous issues with single-page apps were the driving forces for the development of Angular. However, leading businesses in their chosen fields are now placing bets on it. So, it’s necessary to speed up the performance of your app or else it will be thrown out of the competition soon.

As more mobile and web apps are created utilizing the framework, it is evident that Angular will keep on growing. Depending on our expertise, we have created an Angular performance checklist that you may use for Angular development; and to enhance the functionalities of your app. Let’s start!

Make sure to complete Ahead-of-Time (AoT) compilation

AOT ( ahead of time) compilation is the method of transforming Angular HTML and TypeScript code into much more efficient code. This aids in transforming the JavaScript code into a more performant application.

At the building stage, the AOT compiler builds your Angular web or mobile app as well as libraries. It gathers metadata to identify which modules Angular must handle.

AOT compilation is divided into three stages:

Phase 1: is code analysis, in which the TypeScript compiler and AOT collector build a representation of the source.

Phase 2: is code creation, in which the AOT compiler’s StaticReflector decides the metadata obtained in the preceding phase.

Phase 3: is template type checking, in which the Angular template compiler uses the TypeScript compiler to validate the binding expressions. 

Lazy Loading

Lazy loading is another popular strategy for improving performance. However, lazy loading saves time by not loading specific routes and assets such as music, video, and graphics at the start and only loading them when needed.

It will separate a feature with its package and will not load it until required. For example, if the complete app requires 1MB of resources but not all resources are needed at first, separating the routes loads only the homepage and its necessary resources, which is 300KB when the user views the website.

The resulting bundle is more than half the amount of the original!! When the user changes routes, route-specific material is loaded.

This optimization is fantastic since it substantially reduces the ‘Time to interaction’ and aids in the creation of exceptional user experiences. It is relatively simple to lazy load assets with Angular. 

Using Pipes rather than Methods

The Angular pipes approach is best suited for change detection. There are two kinds of pipes: impure pipes and pure pipes.

Pure pipelines decrease the need to recalculate values and complex numbers and further condense the intended outcomes. It only returns values whenever the input differs from previous calls.

As a result, you can reduce the use of functions and methods in the template by replacing them with pipes instead, since a pipe is executed only when input status changes. Still, a process or procedure is called for every change detection. 


Change Detection

When Angular updates dependencies on a page, it employs a unidirectional data transfer. We should know “what is the change detection” in prior. The technique by which Angular changes the corresponding model variables on a view is called “Change Detection”. 

Let’s explore change detection in more detail. Although it’s not strictly comparable to Change Detection, the procedure was called a digest cycle in AngularJS (1.x). The idea is the same.

How Change Detection Works:

The angular app is composed of a component tree, each with its own ‘ChangeDetectorRef’ provider in charge of handling conditional updates specific to that component. When the application is first launched, it generates an ‘ApplicationContext'(root). It calls the ‘tick’ method mainly on the root component, which runs change detection on every element from the upper edge to the bottom of the tree.

Essentially, there are two change detection strategies.

  • OnPush
  • Default


Using ‘trackBy’ for *ngFor directive

*ngFor is used to loop through iterables and deliver them upon the DOM. Although quite helpful, it has a performance issue.

From within, ngFor uses the differences to detect changes in the iterable so that it can re-render. For all of this, the differs employs the strict reference operator ===, which examines object references (memory address).

When we combine this with the immutability practice, we would see that we will tear object references, causing the ngFor to kill and reconstruct the DOM on each iterable.

It will not be a problem for 10-100 elements in an iterable, but when you get to 1000 —, the UI thread will suffer greatly.

ngFor has a trackBy option to track the individuality of components in an iterable.

This will allow the developer to state his individuality in the iterable for the Differ to track. It will prevent the whole DOM from being damaged and reconstructed regularly.


Action Optimization for Better UX

Improving your app’s efficiency is vital to achieving its performance. It is an important area to improve, and the most significant impact on your user experiences is ignored. You can try to improve UX by optimizing activities like error handling in EFFECT or by using CACHED DATA.

Another critical action can be taken to boost the actual quality of your Angular application. This is referred to as Optimistic updating. This method shows in the UI as an update before being stored on the server.

This feature provides consumers with a quick native-like feel. Simultaneously, the server would receive a request without issue. Nevertheless, if an error occurs after the UI change, we must reverse the update. 


Server-side rendering and Service Worker

In server-side rendering, the first webpage is produced on the server and delivered to the client, which renders it immediately on the page. Client-side programming rehydrates the page to make CSR code work. Server-side rendering optimizes page initialization.

SEO and social link previewing depend on SSR. Javascript is disabled when a crawler loads a page. Server-side rendering can help, but it isn’t easy to implement due to a few pitfalls. Check Angular’s documentation.

With the service worker, we may run event-driven programs separately. Shifting primary thread duties improves performance. You can store API responses and HTML pages to speed page load.

This feature enables an app’s offline mode. The service worker gives access to navigation API, which opens the doors to native capabilities like push notifications, geolocation, etc.

Many huge companies want to keep their users satisfied. Thus they focus on TTIB, TFFR, etc., on the landing page to provide non-hesitating behaviour. To solve these concerns, use navigator API, and add @angular/PWA prepares an angular app for PWA.

Server-side rendering is another way of rendering pages. Using Angular universal API, this solution improves FMP metrics.


Use server-side rendering if you want rapid First Meaningful Paint, SEO, and social link previews. 


Removing unused code with tree-shaking

Tree-shaking is a technique for removing unused and outdated code. Not many of the regulations would be necessary for the app’s final version.

Extra code developed by developers or included in the Angular or third-party libraries is essentially worthless and dead. Tree-shaking would remove the code, considerably reducing the size of the angular app.

In addition to the code, unused services can now be removed with Angular 6. Unless they are referenced by other services/components, benefits would not be included in the final build. The best thing is that tree-shaking is enabled by default in Angular CLI. Thus Angular apps are automatically optimized. 

Final Verdict

Following these 8 points of Angular performance optimization, we can indeed say that you will see a positive curve in your app’s performance. Without these practices, the angular app is likely to draw in the sea of competition across the globe. Before hiring angular developers, look at their skills in developing apps using these performance optimization tips.

EnProwess Technologies is a global software and app development Company; we are a group of experienced Angular developers. They have demonstrated their intellect by working on numerous massive projects for our illustrious clientele worldwide.

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