Simple shell script to prune unneeded packages from node_modules. For example, as a pre-processing step when building a Docker image of a Node app in an Nx monorepo that also contains frontend app(s). This reduced our Docker image by ~650 MB.

prune-node-modules.sh

#!/bin/bash

# This script is somewhat unsafe, but may be useful. This script deletes dependencies
# in package.json by deleting any lines that match
# the regexp in the grep, runs yarn install --prod, and then reverts package.json and
# yarn.lock back to their original contents.
# 
# This script assumes yarn 1.x, i.e. yarn classic. If using npm instead of yarn 1.x:
# 1. Replace "yarn.lock" with "package-lock.json"
# 2. Replace "yarn install --prod" with "npm install --only=prod"
#
# The packages that this script is configured to prune are mostly Angular things.
# You can change what packages are pruned by editing the regexp in the grep.

echo 'Removing some packages that are not needed by Node apps in production...'
cp package.json package.json.bak
cp yarn.lock yarn.lock.bak
grep -Eiv 'angular[^\/]|@angular/animations|@angular/cdk|@angular/cdk-experimental|@angular/compiler|@angular/forms|@angular/material|@angular/platform-browser|@angular/platform-browser-dynamic|@angular/router|ngrx|ag-grid|browser|typeface' <package.json.bak >package.json
yarn install --prod || echo 'Ignoring erroneous postinstall error'
echo 'New size of node_modules:'
du -sh * | grep node_modules
rm package.json && rm yarn.lock
mv package.json.bak package.json && mv yarn.lock.bak yarn.lock
echo 'Done.'