Is it possible to install
package only if it has not been already installed?
I need this to speed up test on CircleCI, but when I run
npm install email@example.com
etc. it always downloads things and installs them from scracth, however,
folder with all modules is already present at the moment of running commands (cached from previous build) and
etc. shows the needed version of the package.
Its perfect to have some one-line command like this:
protractor --version || npm install -g firstname.lastname@example.org
but the one that will also check version of the package.