formControlName with or without brackets?

Question

what is the difference between using formControlName inside brackets and without brackets? In the dynamic form tutorial formcontrolname is used inside brackets

[formControlName]="dyncontrol.key"

but in other tutorials i have seen it without them

formControlName="name"

Answer 1

Here's from the Template Syntax documentation:

Remember the brackets

The brackets tell Angular to evaluate the template expression. If we forget the brackets, Angular treats the string as a constant and initializes the target property with that string. It does not evaluate the string!

Don't make the following mistake:

<!-- ERROR: HeroDetailComponent.hero expects a
Hero object, not the string "currentHero" -->
<hero-detail hero="currentHero"></hero-detail>