Javascript string with HTML-CodePudding

I have a component that looks something like this:

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

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
export class AppComponent {
  expandText: boolean = false;

  constructor() {}

  ngOnInit() {}

  stringShortener(text: string) {
    let str = text;

    if (this.expandText === false) {
      if (str.length > 80) {
        str =
          str.substring(0, 80 - 3)  
          '...'  
          ' '  
          "<span style='color: red'>see more</span>";
      }
    } else {
      str = str   '...'   ' '   "<span style='color: yellow'>see more</span>";
    }

    return str;
  }
}

On the HTML side it looks something like:

<div class="wrapper" (click)="expandText = !expandText">
<p>{{ stringShortener("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum") }}</p>
</div>

The issue is, that the HTML of myhtml is not rendered. I have tried with innerHTML, and that resulted in a span in some way. But if the span is something like: <span style="color: red">, or even if I use [ngStyle], [style.color], well, the style is not applied. So I only get a span with the text inside.

So how is this done with the proper rendering ?

EDIT: I have created a Stackblitz that shows the problem: https://stackblitz.com/edit/angular-ivy-xdi3z5?file=src/app/app.component.html

CodePudding user response：

The issue is that you're passing your block with span tag as a text, so Angular just prints it as a normal text.

You can achieve desired functionality with *ngIf directive which will show needed span block, by adding a function which will tell you whether text is too long.

CodePudding user response：

Looks like you forgot the curly braces :)

    <div (click)="expandText= !expandText">
     <p>{{stringShorterner(myText)}}></p>
    </div>

CodePudding user response：

In order to inject rendered HTML into your page you have to use DomSanitizer. This is a security mechanism in Angular - see https://angular.io/api/platform-browser/DomSanitizer for more information.

export class AppComponent {
  expandText: boolean = false;

  constructor(private sanitizer: DomSanitizer) {}

  stringShortener(text: string) {
    let str = text;

    if (this.expandText === false) {
      if (str.length > 80) {
        str =
          str.substring(0, 80 - 3)  
          '...'  
          ' '  
          '<span style="color: red">see more</span>';
      }
    } else {
      str = str   '...'   ' '   "<span style='color: yellow'>see more</span>";
    }

    return this.sanitizer.bypassSecurityTrustHtml(str);
  }
}

Then, in your template you have to use innerHTML:

<div class="wrapper" (click)="expandText = !expandText">
  <p [innerHTML]="stringShortener('Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum')"></p>
</div>