nodebestpractices/sections/docker/clean-cache.md

Clean NODE_MODULE cache

One Paragraph Explainer

Node package managers, npm & Yarn, cache the installed packages locally so that future projects which need the same libraries won't need to fetch from a remote repository. Although this duplicates the packages and consumes more storage - it pays off in a local development environment that typically keeps installing the same packages. In a Docker container, this storage increase is worthless since it installs the dependency only once. By removing this cache, using a single line of code, tens of MB are shaved from the image. While doing so, ensure that it doesn't exit with non-zero code and fail the CI build because of caching issues - This can be avoided by including the --force flag

Code Example – Clean cache

Dockerfile

FROM node:12-slim AS build
WORKDIR /usr/src/app
COPY package.json package-lock.json ./
RUN npm ci --production && npm clean cache --force

# The rest comes here