I like the idea of repeating the delimiter on every line. However `//` looks like a comment to me. I could simply choose double quote:
const still_raw =
"const raw =
" "Roses are red
" " Violets are blue,
" "Sugar is sweet
" " And so are you.
" "
";
"
;
This cannot be confused with a string literal because a string literal cannot contain newline feeds.
What if you have something like
Wouldn't that be a mess to parse? How would you know that "He said " is not a string literal and that you have to continue parsing it as a multiline string? How would you distinguish an unclosed string literal from a multiline string?