js--opt-cpp-start

js--opt-cpp-start is a variable defined in `js.el'.
Its value is

"^\\s-*#\\s-*\\([[:alnum:]]+\\)"

• This variable may be risky if used as a file-local variable.

Documentation:
Regexp matching the prefix of a cpp directive.
This includes the directive name, or nil in languages without
preprocessor support. The first submatch surrounds the directive
name.