javascript - Angular: Show placeholder image if img src is not valid

Javascript - Angular: Show placeholder image if img src is not valid

In Angular, you can show a placeholder image if the img source is not valid by using the onerror event in combination with a placeholder image source. Here's an example:

  1. Create a placeholder image and include it in your assets folder:

    Place a placeholder image (e.g., placeholder.jpg) in the src/assets folder of your Angular project.

  2. Update your component HTML template:

<!-- app.component.html --> <img [src]="imageUrl" (error)="handleImageError()" alt="Image" />
  1. Update your component TypeScript file:
// app.component.ts import { Component } from '@angular/core'; @Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'], }) export class AppComponent { // Set the initial image source to an invalid URL imageUrl = 'invalid-url'; // Placeholder image source placeholderImageUrl = 'assets/placeholder.jpg'; // Handle image load error by setting the source to the placeholder image handleImageError() { this.imageUrl = this.placeholderImageUrl; } }

In this example, the imageUrl is initially set to an invalid URL. If the img element encounters an error (such as a failed load), the handleImageError method is triggered. Inside this method, we set the imageUrl to the source of the placeholder image.

Ensure that you replace 'invalid-url' with your actual image source or dynamically update the imageUrl based on your application logic. Also, update the alt attribute with a meaningful description for accessibility.

Examples

  1. "Angular show placeholder image if img src is not found"

    • Code Implementation:
      <img [src]="imageUrl" (error)="handleImageError($event)"> 
      imageUrl: string = 'path/to/valid-image.jpg'; handleImageError(event: Event): void { const imgElement = event.target as HTMLImageElement; imgElement.src = 'path/to/placeholder-image.jpg'; }
    • Description: Uses the (error) event to detect when the image fails to load and replaces it with a placeholder.

  2. "Angular ngIf with img element for fallback image"

    • Code Implementation:
      <ng-container *ngIf="isValidImage; else placeholder"> <img [src]="imageUrl" (error)="isValidImage = false"> </ng-container> <ng-template #placeholder> <img src="path/to/placeholder-image.jpg"> </ng-template> 
      isValidImage: boolean = true; imageUrl: string = 'path/to/valid-image.jpg';
    • Description: Uses ngIf to conditionally render the image based on its validity and includes a fallback placeholder image.

  3. "Angular pipe for image fallback"

    • Code Implementation:
      <img [src]="imageUrl | imageFallback:'path/to/placeholder-image.jpg'"> 
      imageUrl: string = 'path/to/valid-image.jpg'; 
      // image-fallback.pipe.ts import { Pipe, PipeTransform } from '@angular/core'; @Pipe({ name: 'imageFallback' }) export class ImageFallbackPipe implements PipeTransform { transform(imageUrl: string, fallback: string): string { return imageUrl || fallback; } }
    • Description: Defines a custom pipe (imageFallback) to handle fallback logic for images.

  4. "Angular onError event binding for image fallback"

    • Code Implementation:
      <img [src]="imageUrl" (error)="imageUrl = 'path/to/placeholder-image.jpg'"> 
      imageUrl: string = 'path/to/valid-image.jpg';
    • Description: Directly binds the (error) event to update the image source in case of an error.

  5. "Angular directive for fallback image"

    • Code Implementation:
      <img [src]="imageUrl" appImageFallback="path/to/placeholder-image.jpg"> 
      imageUrl: string = 'path/to/valid-image.jpg'; 
      // image-fallback.directive.ts import { Directive, Input, HostListener, Renderer2, ElementRef } from '@angular/core'; @Directive({ selector: '[appImageFallback]' }) export class ImageFallbackDirective { @Input() appImageFallback: string = ''; constructor(private el: ElementRef, private renderer: Renderer2) {} @HostListener('error') onError(): void { this.renderer.setAttribute(this.el.nativeElement, 'src', this.appImageFallback); } }
    • Description: Implements a directive (appImageFallback) to handle fallback logic for images.

  6. "Angular ngIf with async pipe for image loading"

    • Code Implementation:
      <ng-container *ngIf="imageUrl$ | async as imageUrl; else placeholder"> <img [src]="imageUrl" (error)="handleImageError($event)"> </ng-container> <ng-template #placeholder> <img src="path/to/placeholder-image.jpg"> </ng-template> 
      imageUrl$: Observable<string> = of('path/to/valid-image.jpg');
    • Description: Uses the async pipe with an observable for dynamic image loading and includes a placeholder for errors.

  7. "Angular ngStyle for image fallback styling"

    • Code Implementation:
      <img [src]="imageUrl" [ngStyle]="{'background-image': 'url(' + imageUrl + ')'}" (error)="imageUrl = 'path/to/placeholder-image.jpg'"> 
      imageUrl: string = 'path/to/valid-image.jpg';
    • Description: Applies a background image style using ngStyle for fallback styling in case of image load failure.

  8. "Angular safe navigation operator with image fallback"

    • Code Implementation:
      <img [src]="imageUrl?.length > 0 ? imageUrl : 'path/to/placeholder-image.jpg'"> 
      imageUrl: string = 'path/to/valid-image.jpg';
    • Description: Uses the safe navigation operator (?.) to handle fallback if imageUrl is null or undefined.

  9. "Angular async pipe with default value for image loading"

    • Code Implementation:
      <img [src]="(imageUrl$ | async) || 'path/to/placeholder-image.jpg'"> 
      imageUrl$: Observable<string> = of('path/to/valid-image.jpg');
    • Description: Utilizes the async pipe with an observable and a default value for image loading.

  10. "Angular template reference variable for image fallback"

    • Code Implementation:
      <img [src]="imageUrl" #imgRef (error)="imgRef.src = 'path/to/placeholder-image.jpg'"> 
      imageUrl: string = 'path/to/valid-image.jpg';
    • Description: Uses a template reference variable (#imgRef) to directly manipulate the image source on error.

More Tags

angular2-pipe ms-access-2016 jpos azure-eventgrid java-http-client coordinator-layout react-dnd pester file-sharing soql

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