[angular] How to use Angular4 to set focus by element id

One of the answers in the question referred to by @Z.Bagley gave me the answer. I had to import Renderer2 from @angular/core into my component. Then:

const element = this.renderer.selectRootElement('#input1');

// setTimeout(() => element.focus, 0);
setTimeout(() => element.focus(), 0);

Thank you @MrBlaise for the solution!