Ruby image with node & yarn

Dockerfile

FROM ruby:2.6-slim

RUN apt-get update && apt-get install -y --no-install-recommends \
  build-essential \
  curl \
  gnupg \
  git \
  # substitute 12.x with whichever Node version you require:
  && curl -sL https://deb.nodesource.com/setup_12.x | bash - \
  && curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - \
  && echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
  && apt-get update && apt-get install -y --no-install-recommends \
  nodejs \
  yarn \
  && rm -rf /var/lib/apt/lists/*

RUN mkdir /app
WORKDIR /app

ADD package.json /app/package.json
ADD yarn.lock /app/yarn.lock
RUN yarn --pure-lockfile

ADD Gemfile /app/Gemfile
ADD Gemfile.lock /app/Gemfile.lock
RUN bundle install --jobs 4
ADD . /app