functions for common npm tasks

npm-commons.sh

#!/usr/bin/env bash

##################################
# functions for common npm tasks #
##################################



##### public #####


#
# removes 'node_modules', clears the cache and installs everything
#
# output:
# whatever npm outputs
#
npm_restart() {
        rm -rf node_modules && npm cache clear && npm i
}
alias npm_reboot=npm_restart
alias npm_again=npm_restart

#
# uninstalls and installs a package
#
# input:
# $1 - the package name
#
# output:
# whatever npm outputs
#
npm_package_reinstall() {
        __defensive_proxy __npm_package_reinstall $1
}
alias npm_pack_rein=npm_package_reinstall
alias npmpr=npm_package_reinstall

#
# pass a package name and get its locally installed version
#
# input:
# $1 - the package name
#
# output:
# the package version string
#
npm_package_version() {
        __defensive_proxy __npm_package_version $1
}
alias npm_pack_ver=npm_package_version
alias npmpv=npm_package_version

#
# installs a package version that is stable.
# this implementation uses the version previous to the latest published version.
#
# input:
# $1 - the package name
#
# output:
# whatever npm outputs
#
npm_package_stabilize() {
	__defensive_proxy __npm_package_stabilize $1
}
alias npm_pack_sta=npm_package_stabilize
alias npmps=npm_package_stabilize

#
# installs a package version that is previous to the currently installed local version
#
# input:
# $1 - the package name
#
# output:
# whatever npm outputs
#
npm_package_downgrade() {
	__defensive_proxy __npm_package_downgrade $1
}
alias npm_package_revert=npm_package_downgrade
alias npm_pack_down=npm_package_downgrade
alias npmpd=npm_package_downgrade



##### private #####

#
# a predicate that checks if the passed argument is of type function
#
# input:
# $1 - the variable to test
#
# output:
# true if the passed argument is a function, false otherwise
#
__is_function() {
	[[ "`type -t $1`" = "function" ]]
}

#
# a predicate that checks if the passed argument is not empty
#
# input:
# $1 - the variable to test
#
# output:
# true if the passed argument is not empty, false otherwise
#
__is_not_empty() {
	[[ "$1" != "" ]]
}

#
# checks for the presence of a proxied function's single argument and delegates the invocation
#
# input:
# $1 - the proxied function
# $2 - the proxied function's sole argument
#
# output:
# the invocation result, if the argument is valid, or an empty string otherwise
#
__defensive_proxy() {
        if $(__is_function $1) && $(__is_not_empty $2); then
		local result=$($@)
        fi
        echo $result
}

#
# returns an aggregation of all passed parameters as a single space-delimited-string,
# clearing array-like delimiters.
# use with command substitution to get the returned value, e.g. $(__as_space_delimited_string [ a, b ]).
#
# input:
# $@ - 	a virtual argument in the form of a json array, representing all passed arguments
# 	(to allow empty spaces in the parameter),
#
# output:
# a bash array containing the json array data
#
__as_space_delimited_string() {
	# lose these characters: ,'[]
	echo $@ | sed "s/[,']//g" | sed "s/\[//g" | sed "s/\]//g"
}

#
# gets the index of a value in an array
#
# input:
# $1 - the value to search for
# $2 - the array containing the value
#
# output:
# the index of the passed value in the passed array
#
__index_of() {
	local value="$1"
	declare -a array=("${!2}")
	local count=0;
	for item in "${array[@]}"; do
	        [[ $item == "$value" ]] && echo $count && break
		((++count))
	done
}

#
# returns the package's publicly available versions as a space-delimited string
#
# input:
# $1 - the package name
#
# output:
# the package's public versions as a string
#
__npm_package_versions_as_string() {
	local available_versions=$(npm show $1 versions)
	echo $(__as_space_delimited_string $available_versions)
}

# see: npm_package_stabilize
__npm_package_stabilize() {
	local versions_string=$(__npm_package_versions_as_string $1)
	local versions_array=(${versions_string})
	local prev_public_version=${versions_array[-2]}
	npm i $1@$prev_public_version
}

# see: npm_package_version
__npm_package_version() {
	echo $(cut -d "@" -f 2 <<< `npm ls $1 | grep $1`)
}

# see: npm_package_reinstall
__npm_package_reinstall() {
        npm un $1 && npm i $1
}

# see: npm_package_downgrade
__npm_package_downgrade() {
	local current_version=$(__npm_package_version $1)
	local versions_string=$(__npm_package_versions_as_string $1)
	local versions_array=(${versions_string})
	local current_version_index=$(__index_of $current_version versions_array[@])
	if $(__is_not_empty $current_version_index); then
		local prev_version_index=$(($current_version_index - 1))
	fi
	if $(__is_not_empty $prev_version_index); then
		local prev_version=${versions_array[$prev_version_index]}
		npm i $1@$prev_version
	fi
}

source this script from the shell / your script, copy & paste it to your .bashrc, do whatever your feel like :)