Is it possible to install npm package only if it has not been already installed?
Function version of the excellent answer by @JeromeWAGNER:
function install_package_if_needed() { local p=${1:-Package required} local v=${2:-Version required} shift 2 local i=$(node -p "require('$p/package.json').version" 2>/dev/null) [ "$i" == "$v" ] || npm "$@" install "$p@$v"}Use like:
$ install_package_if_needed protractor 2.1.0To pass additional options to npm, specify them after the version, like so:
$ install_package_if_needed protractor 2.1.0 -g