Git-hook to create a tag automatically based on lately committed package.json version

post-commit

#! /bin/bash
version=`git diff HEAD^..HEAD -- "$(git rev-parse --show-toplevel)"/package.json | grep -m 1 '^\+.*version' | sed -s 's/[^A-Z0-9\.\-]//g'`

if [[ ! $version =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)(\-[A-Z]+\.[0-9]+)?$ ]]; then
    echo -e "Skip tag: invalid version '$version'"
    exit 1
fi

git tag -a "v$version" -m "`git log -1 --format=%s`"
echo "Created a new tag, v$version"

This is incredibly useful. Thank you!

One note for anyone on OS X, you will need to remove the -s flag from the sed call on line 2