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javascript - Angular 2 conditionally add attribute directives

I've seen two questions here how to conditionally add and remove attributes on an item (Is it possible to conditionally display element attributes using Angular2?) but my question is if it is possible to add and remove attribute directives ? I am able to add and remove the attribute but Angular does not "compile" the attribute as an attribute directive but the attribute just sits there doing nothing. Here is an example of 2 tags:

The first one is the one that I am trying to conditionally apply the attribute directive and the second one has it all the time.

Here is the gif: enter image description here

Here is how I am applying the attribute (maybe there is a different way to apply attribute directive?)

<h1 [attr.colored]="check ? '': null">Testing something</h1>

And here is the directive:

import {Directive, ElementRef} from '@angular/core'
@Directive({
    selector: '[colored]',
    host: {
        '(mouseenter)': 'onMouseEnter()',
        '(mouseleave)': 'onMouseLeave()'
    }
})

export class colorDirective {
    constructor(private el: ElementRef) {
    }
    onMouseEnter() { this.highlight("yellow"); }
    onMouseLeave() { this.highlight(null); }

    private highlight(color: string) {
        this.el.nativeElement.style.backgroundColor = color;
    }
}

Edit: There are couple answers but they are for AngularJS (1)

See Question&Answers more detail:os

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That is not supported. Directives are only applied when static HTML matches the selector.


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