js--make-merged-item
js--make-merged-item is a compiled Lisp function in `js.el
'.
(js--make-merged-item ITEM CHILD NAME-PARTS)
Helper function for `js--splice-into-items'.
Return a new item that is the result of merging CHILD into
ITEM. NAME-PARTS is a list of parts of the name of CHILD
that we haven't consumed yet.