How does AWS Beanstalk use NPM when deploying a Nodejs App?

I'm curious about the overall workflow of an AWS Beanstalk deployment. I'm assuming it runs npm at some point to get the packages installed on the server(s). But I was just wondering if AWS Beanstalk uses the latest command of 'npm install --production' to install packages. Currently I have a packages.json file as shown below and would like to insure if possible that only the dependencies are being installed and not the devDependencies.

"dependencies": {
  "express": "3.4.4",
  "jade": "*",
  "restify": "~2.6.0",
  "assert": "~1.0.0",
  "orchestrate": "0.0.2",
  "chance": "~0.5.3"
}, 
"devDependencies": {
  "mocha": "~1.15.1"
}