toSpacedUpperCase method
Converts to UPPER CASE (space-separated, all uppercase).
Named toSpacedUpperCase to avoid shadowing String.toUpperCase.
'helloWorld'.toSpacedUpperCase(); // 'HELLO WORLD'
'some_snake_case'.toSpacedUpperCase(); // 'SOME SNAKE CASE'
Implementation
String toSpacedUpperCase() => _words.map((w) => w.toUpperCase()).join(' ');