How do I unit test if an element is visible when the *ngIf directive is used using Jasmine in Angular

Question

I have an Angular 6 app and writing some unit tests trying to determine if an element is visible or not based solely on the boolean result of an *ngIf directive

Answer 1

If the element is hidden, then it wont be rendered inside the dom.

You can check

expect(fixture.debugElement.query(By.css('.header'))).toBeUndefined();

EDIT : toBeNull() works better in the above case

expect(fixture.debugElement.query(By.css('.header'))).toBeNull();

And also you have a syntax error while fetching the button element. nativeElement is not a function.

Change it this way :

const button = fixture.debugElement.query(By.css('button')).nativeElement;