javascript - Angular - How to check if a component tag has specific attribute on it?

Question

I use the app-somecomponent in the following way

<app-somecomponent required></app-somecomponent>

How do I check if app-somecomponent has the required attribute from the app-somecomponent.component.ts? I don't wan't to use any value for the required attribute (so [required]="true", for instance is not allowed)

About the - AngularJS equivalent for hasAttribute()? - the $attr is not available in the newer versions of Angular.

Answer 1

Try

  @Input() required;
  isRequired: boolean;

  ngOnInit() {
    this.isRequired = this.required !== undefined;
  }

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