Git hook to install npm dependencies after a `git pull`. Run `chmod +x post-merge` and put it in `.git/hooks/`. Though could really do whatever.

post-merge

#!/bin/sh
npm install

Your example is really easy, but I need something a bit more complicated:
how is it possible to trigger an npm install or bower install on a post merge ONLY if my local package.json or bower.json gets updated?

Working in big team, anytime someone installs a new grunt or bower dependency he must communicate that by voice or chat to all the other developers so it would be great to trigger it just by git pull if necessary

Another idea could be also to trigger any npm or bower command by checking the commit messages example:

added the new jquery slider carousel :: bower install jquery

what's your opinion?

You could save the MD5 hashsum of package.json and check if it changes between merges, but that's really just overcomplicating it. Can't you just always run npm install & bower install after every merge? If nothing has changd they won't do anything.

I think running npm install & bower install on any git pull is not really an elegant solution for three reasons:

• this really means that pulling a project every 10/15 minutes ( like often we do ) it will trigger many other useless npm and bower commands that could take at least ~30seconds per each ( imagine how many seconds wasted )
• npm install and bower install do not delete the old packages already fetched
• this solution does not work if you then add the composer commands ( we work mostly on Laravel projects )

I created a quick script for you. Let me know how it works: https://gist.github.com/sindresorhus/7996717

+1 to latest script

this doesn't work for me with zsh and nvm - can't find npm

@pajtai see nvm-sh/nvm#688 (comment) (googled for "git hook nvm path")... don't be so lazy and do some research 🤓 your problem is not related to this script.

#!/usr/bin/env bash

set -e

prevHEAD=$1
newHEAD=$2
checkoutType=$3

[[ $checkoutType == 1 ]] && checkoutType='branch' ||
checkoutType='file' ;

check_run() {
    echo "$changed_files" | grep --quiet "$1" && eval "$2"
}

[[ $checkoutType = 'branch' ]] && {
    
    changed_files="$(git diff-tree -r --name-only --no-commit-id $prevHEAD $newHEAD)"
    
    # node - use whichever works for you
    check_run yarn.lock "yarn install"
    # check_run package-lock.json "npm install"

   # composer
    check_run composer.lock "composer install"
}