Angular2 Component selector: array like '[ui-components]'

Question

I've realized sometimes I've seen angular2 code as:

@Component({
  selector: '[ui-components]'

What does selector: '[ui-components] mean?

Answer 1

It means you are making the component as an attribute component instead of an element component. When you use the component in your html, you write

<div ui-components></div>

if you use

@Component({
  selector: 'ui-components' // without the brackets

you have to use this notation in your html

<ui-components></ui-components>

Here are some readings from the Angular2 documentation.