Angular - 在指令的构造函数中使用 Renderer2

Question

I want to migrate an Angular app to a higher version and one the steps is to replace Renderer with Renderer2 , and I have a problem because Renderer2 seems to be not defined inside the constructor:

constructor(private el: ElementRef, private renderer: Renderer2) {
    renderer.setAttribute(el.nativeElement, "data-id", this.uniqueId);
}

So I get an error which says:

TypeError: Cannot read property 'setAttribute' of undefined

Do I have to move renderer.setAttribute(...) into OnInit or something like that? With Renderer this worked fine, but with Renderer2 it no longer works.

Current Angular version: 5.2.10

Please advise. Thanks!

Answer 1

I add do this on ngAfterViewInit . That means after first render!

I would also check explicit If the element is already initialized and maybe add a retry policy. if(el)el.nativeElement... (If your element is inside a *ngIf directive).