May 23, 2021 Dart Code style guide
You should avoid using braces when you don't need to.
If you just insert a simple identifier and there is no other text at the end of that
{}
can delete it.
// good
'Hi, $name!'
"Wear your wildest $decade's outfit."
'Wear your wildest ${decade}s outfit.'
// bad
'Hi, ${name}!'
"Wear your wildest ${decade}'s outfit."