Node js Get folder path from a file

Is there a way to get the path to a folder that holds a particular file.

fs.realpathSync('config.json', []);

returns something like

G:\node-demos\7-node-module\demo\config.json

I just need

G:\node-demos\7-node-module\demo\ 
or
G:\node-demos\7-node-module\demo\

Is there any api for this or will I need to process the string?

use path.dirname

// onlyPath should be G:\node-demos\7-handlebars-watch\demo
var onlyPath = require('path').dirname('G:\node-demos\7-node-module\demo\config.json');