Caching node_modules in Jenkins

This is a basic implementation. For true CI/CD, it's advised that you review how this integrates into your process carefully.

#!/usr/bin/env bash

FILECHECKSUM=$(sha1sum yarn.lock|grep -o '^\S*')
echo "yarn.lock hash is ${FILECHECKSUM}"

CHECKSUM_NODE_MODULES=${JENKINS_HOME}/"${FILECHECKSUM}_node_modules"

if [ -f "$CHECKSUM_NODE_MODULES" ]; then
	echo "Found matching node_modules folder. Extracting"
    tar xf $CHECKSUM_NODE_MODULES.tar.gz
fi

yarn install --frozen-lockfile;

if [ ! -f "$CHECKSUM_NODE_MODULES" ]; then
    echo "No matching node_modules folder was found. Archiving this one"
	tar cfz "${CHECKSUM_NODE_MODULES}.tar.gz" node_modules
fi