node --version # 4.2.4
npm --version # 2.14.12
npm i # notice that there are no warnings.
npm shrinkwrap --dev
rm -rf node_modules
npm i # now there is a warning about browserify being auto installed as a peerDependency
If a dependency or devDependency is explicitly listed in the package.json
it shouldn't
become a peerDependency from the perspective of a shrinkwrap install.