Code:
  (lambda ()
    (setq indent-tabs-mode nil)
    (heex-ts-mode)
    (indent-region (point-min) (point-max)))

Point-Char: $

Name: Tag

=-=
   <div>
 div
    </div>
=-=
<div>
  div
</div>
=-=-=

Name: Component

=-=
   <Foo>
     foobar
      </Foo>
=-=
<Foo>
  foobar
</Foo>
=-=-=

Name: Slots

=-=
   <Foo>
   <:bar>
     foobar
      </:bar>
      </Foo>
=-=
<Foo>
  <:bar>
    foobar
  </:bar>
</Foo>
=-=-=

Name: Expression

=-=
<div>
{
@bar
}
</div>
=-=
<div>
  {
    @bar
  }
</div>
=-=-=