Usually we run :
npm start
to start an app, then we we might call other script to do something:
npm build && nodemon app
Actaully we can use "prestart" to simpify this, because npm will check if there is "prestart" script, if there is it will run prestart before start:
"prestart": "babel src --out-dir dist",
"start": "node dist/index.js"
[Node.js] Use "prestart" in scripts
原文：http://www.cnblogs.com/Answer1215/p/5277772.html