https://stackoverflow.com/questions/12478679/npm-install-vs-update-whats-the-difference
update의 경우 있는 모듈도 최신화, install은 있는 모듈은 설치 x
Summary: The only big difference is that an already installed module with fuzzy versioning ...
npm install
npm update
Additionally: install
and update
by default handle devDependencies differently
npm install
will install/update devDependencies unless --production
flag is added
npm update
will ignore devDependencies unless --dev
flag is added
manually install node-modules
set them as global (which puts them in the shell's PATH
) using npm install -g <name>
install certain versions described by git tags
install from a git url
force a reinstall with --force