put debug output behind a flag.

Every time you open a javascript file, it echoes the fact that it added
node_modules to the path, which, when the package is operating as
expected is mostly noise.

This enhances the debug output to not only include the exact
directories which are added to the `exec-path`, but also to only
output when the debug flag, `add-node-modules-path-debug` is turned
on.

Author: cowboyd

add-node-modules-path.el

@@ -31,8 +31,14 @@
 
 ;;; Code:
 
+;;;###autoload
+(defvar add-node-modules-path-debug nil
+  "Enable verbose output when non nil.")
+
 ;;;###autoload
 (defun add-node-modules-path ()
+  "Search the current buffer's parent directories for `node_modules/.bin`.
+If it's found, then add it to the `exec-path'."
   (let* ((root (locate-dominating-file
                 (or (buffer-file-name) default-directory)
                 "node_modules"))
@@ -42,8 +48,10 @@
         (progn
           (make-local-variable 'exec-path)
           (add-to-list 'exec-path path)
-          (message "added node_modules to exec-path"))
-      (message "node_modules not found"))))
+          (when add-node-modules-path-debug
+            (message (concat "added " path  " to exec-path"))))
+      (when add-node-modules-path-debug
+        (message (concat "node_modules not found in " root))))))
 
 (provide 'add-node-modules-path)