js--guess-function-name

js--guess-function-name is a compiled Lisp function in `js.el'.

(js--guess-function-name POSITION)

Guess the name of the JavaScript function at POSITION.
POSITION should be just after the end of the word "function".
Return the name of the function, or nil if the name could not be
guessed.

This function clobbers match data. If we find the preamble
begins earlier than expected while guessing the function name,
set `js--guess-function-name-start' to that position; otherwise,
set that variable to nil.