Wrong example

[bnbarak]

When getting the error:

Running "babel:dist" (babel) task
Warning: Path must be a string. Received undefined Use --force to continue.

The solution is to change the dist object from src to path
dist: { path: { './server.js': 'src/app.js' } }

At least in versions
"babel-preset-es2015": "^6.24.1", "babel-preset-stage-2": "^6.24.1", "grunt-babel": "^6.0.0"

Also need to change the example.