Installing node (& npm) on a mongo:4.0-xenial docker base image

Dockerfile

# base image uses node latest minor version of 12.m
#FROM node:12-stretch-slim
FROM mongo:4.0-xenial

# create and set cwd
WORKDIR /code

# copy npm's package state files 
COPY package.json .
COPY package-lock.json .

RUN apt update

RUN apt install -y curl sudo

RUN curl -fsSL https://deb.nodesource.com/setup_15.x | sudo -E bash -
RUN apt install -y nodejs

#RUN apt install npm

# install all required dependency packages (see package.json)
RUN npm install

# copy the project directory & code in
COPY . .

# prefer port 3001
EXPOSE 3001

# invoke 'npm start' command
ENTRYPOINT [ "npm", "start" ]
#CMD [ "start" ]