Executing a function in the view/template with Angular 2+

Question

Executing a function in the view/template with Angular 2+

Whenever a function is called in the view of an Angular component, it seems to be executed repeatedly. A typical example of this scenario can be seen below:

nightclub.component.ts

import { Component } from '@angular/core';

@Component({
  selector: 'app-nightclub',
  templateUrl: './nightclub.component.html',
  styleUrls: ['./nightclub.component.css']
})
export class NightclubComponent {
  doStuff(): number {
    return 1;
  }
}

nightclub.component.html

{{doStuff()}}

As observed, the doStuff() method is constantly being invoked.

Question:

Is it recommended to have functions called repeatedly in this manner? If so, under what circumstances could this practice prove to be advantageous?

javascript angular typescript angular-components

Answer 1

Answer №1

It is recommended to avoid using a function inside the template, as it will be called every change detection cycle and can result in a performance impact.

The way you implement the function or data displayed on the template greatly depends on your specific use case.

For example:

If you are parsing text, using a pipe would be an efficient choice since it can be memoized.

If changes to the data may occur outside of the component where Inputs and Outputs cannot be utilized, then using an Observable is a good solution.

Answer 2

It is recommended to avoid using a function inside the template, as it will be called every change detection cycle and can result in a performance impact.

The way you implement the function or data displayed on the template greatly depends on your specific use case.

For example:

If you are parsing text, using a pipe would be an efficient choice since it can be memoized.

If changes to the data may occur outside of the component where Inputs and Outputs cannot be utilized, then using an Observable is a good solution.

Answer 3

Answer №2

Aside from the responses and comments, I would like to offer some suggestions to enhance your code optimization. To begin with, I recommend watching this informative video (~40 minutes) from ng-conf on optimizing Angular applications by Minko Gechev.

The key takeaway is to implement the OnPush change detection strategy in your components, utilize Pure Pipes for methods like the one in your example, and consider memoizing functions.

If you have the OnPush Strategy enabled in your Component but changes are coming from outside of Angular's control, you can also inject ChangeDetectorRef into your component and manually invoke markForCheck() (for more information, refer to the official documentation).

Answer 4

Aside from the responses and comments, I would like to offer some suggestions to enhance your code optimization. To begin with, I recommend watching this informative video (~40 minutes) from ng-conf on optimizing Angular applications by Minko Gechev.

The key takeaway is to implement the OnPush change detection strategy in your components, utilize Pure Pipes for methods like the one in your example, and consider memoizing functions.

If you have the OnPush Strategy enabled in your Component but changes are coming from outside of Angular's control, you can also inject ChangeDetectorRef into your component and manually invoke markForCheck() (for more information, refer to the official documentation).

Executing a function in the view/template with Angular 2+

Question:

Answer №1

Answer №2

Similar questions

What could be causing my insertRow function to inject empty cells into my table?

Error: The Vue Class-Based module failed to parse due to an unexpected character '@'

Setting up NextJs in Visual Studio Code with Yarn

Nested self-referencing in Typescript involves a structure where

The TypeScript generated definition file (.d.ts) is failing to work properly in conjunction with the typings specified in package.json

Can information be saved to a JSON file without using a server-side language?

AngularJS is restricting the use of square brackets within the URL parameter, specifically the character '[.'

The GitHub Pages website is not displaying exactly like it does when running locally with a live server

Adjust the width of a div based on its height dimension

Angular: NaNa: Attempting to access a property of an undefined variable

How to efficiently transfer data between PHP and Javascript using ajax?

Using inline style instead of relying on the quill editor's built-in classes, as classes may not be accessible in order to render HTML effectively

Sveltekit: Troubleshooting problem of refreshing when utilizing store and localStorage

Automatically transitioning from a chatbot interface to an Ionic mobile app page as the conversation progresses

Error during the production build of Next.js Internationalized Routing: Prerendering page encountered an unexpected issue

Learn how to seamlessly integrate React Hooks Form with the Select component from @Mui for a powerful

Error handling in Angular is not properly managing the custom exception being thrown

Is there a way to customize the progress bar percentage in Ant design?

I'm experiencing difficulties with a JavaScript slideshow in Vegas

The outer border of the Angular Material Mat Grid List is beautifully highlighted