Error Encyclopedia

Invalid Shadow DOM selector

The selector of a component using ViewEncapsulation.ShadowDom doesn't match the custom element tag name requirements.

In order for a tag name to be considered a valid custom element name, it has to:

  • Be in lower case.
  • Contain a hyphen.
  • Start with a letter (a-z).

Debugging the error

Rename your component's selector so that it matches the requirements.

Before:

      
@Component({  selector: 'comp',  encapsulation: ViewEncapsulation.ShadowDom  …})

After:

      
@Component({  selector: 'app-comp',  encapsulation: ViewEncapsulation.ShadowDom  …})