*ngIf and *ngFor on same element causing error

Question

I\'m having a problem with trying to use Angular\'s *ngFor and *ngIf on the same element.

When trying to loop through the collection in th

Answer 1

You can not use more than one Structural Directive in Angular on the same element, it makes a bad confusion and structure, so you need to apply them in 2 separate nested elements(or you can use ng-container), read this statement from Angular team:

One structural directive per host element

Someday you'll want to repeat a block of HTML but only when a particular condition is true. You'll try to put both an *ngFor and an *ngIf on the same host element. Angular won't let you. You may apply only one structural directive to an element.

The reason is simplicity. Structural directives can do complex things with the host element and its descendents. When two directives lay claim to the same host element, which one takes precedence? Which should go first, the NgIf or the NgFor? Can the NgIf cancel the effect of the NgFor? If so (and it seems like it should be so), how should Angular generalize the ability to cancel for other structural directives?

There are no easy answers to these questions. Prohibiting multiple structural directives makes them moot. There's an easy solution for this use case: put the *ngIf on a container element that wraps the *ngFor element. One or both elements can be an ng-container so you don't have to introduce extra levels of HTML.

So you can use ng-container (Angular4) as the wrapper (will be deleted from the dom) or a div or span if you have class or some other attributes as below:

  

    {{log(thing)}}
    {{thing.name}}