post-receive Git hook for building and serving React application

post-receive

#!/bin/bash
TARGET="<target-location>"
DEPLOY="<deployment-location>"
GIT_DIR="<repo-location>"
BRANCH="master"

while read oldrev newrev ref
do
	# only checking out the master (or whatever branch you would like to deploy)
	if [ "$ref" = "refs/heads/$BRANCH" ];
	then
		filelist=$(git diff-tree --no-commit-id --name-only -r $newrev)
		echo "Ref $ref received. Deploying ${BRANCH} branch to production..."
		git --work-tree=$TARGET --git-dir=$GIT_DIR checkout -f $BRANCH
		cd $TARGET
		if [[ $filelist == *"package.json"* || $filelist == *"package-lock.json"* ]]; 
		then
			echo "Changes detected in Package files..."
			echo "Reinstalling dependencies..."
			npm i --only=prod
		fi
		echo "Building UI..."
		npm run build
		echo "Redeploying UI..."
		rm -rf $DEPLOY/*
		cp -r $TARGET/build/* $DEPLOY/
	else
		echo "Ref $ref received. Doing nothing: only the ${BRANCH} branch may be deployed on this server."
	fi
done