Install node and npm with nvm using Docker.

build.sh

#!/usr/bin/env bash

# confirm docker daemon is running and connected
docker version

# build the image based on the Dockerfile and name it `nvm`
docker build -t nvm .

# confirm image is present
docker images

# enter container terminal
docker run -it nvm bash

Dockerfile

# set the base image to Debian
# https://hub.docker.com/_/debian/
FROM debian:latest

# replace shell with bash so we can source files
RUN rm /bin/sh && ln -s /bin/bash /bin/sh

# update the repository sources list
# and install dependencies
RUN apt-get update \
    && apt-get install -y curl \
    && apt-get -y autoclean

# nvm environment variables
ENV NVM_DIR /usr/local/nvm
ENV NODE_VERSION 4.4.7

# install nvm
# https://github.com/creationix/nvm#install-script
RUN curl --silent -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.2/install.sh | bash

# install node and npm
RUN source $NVM_DIR/nvm.sh \
    && nvm install $NODE_VERSION \
    && nvm alias default $NODE_VERSION \
    && nvm use default

# add node and npm to path so the commands are available
ENV NODE_PATH $NVM_DIR/v$NODE_VERSION/lib/node_modules
ENV PATH $NVM_DIR/versions/node/v$NODE_VERSION/bin:$PATH

# confirm installation
RUN node -v
RUN npm -v

Here is my solution which doesn't care about version numbers but installs latest npm and node LTS, doesn't use any symlinks, doesn't mess up with $PATH and /bin/sh but uses a login shell:

FROM debian:buster

ARG DEBIAN_FRONTEND=noninteractive

SHELL ["/bin/bash", "-l", "-euxo", "pipefail", "-c"]

RUN apt-get update; \
    apt-get full-upgrade -y; \
    apt-get install -y --no-install-recommends \
        ca-certificates \
        curl \
    ; \
    apt-get clean; \
    rm -rf /var/lib/apt/lists/*

ENV NVM_DIR /usr/local/nvm

RUN mkdir -p "$NVM_DIR"; \
    curl -o- \
        "https://raw.githubusercontent.com/nvm-sh/nvm/master/install.sh" | \
        bash \
    ; \
    source $NVM_DIR/nvm.sh; \
    nvm install --lts --latest-npm

RUN command -v nvm; \
    command -v node; \
    node --version; \
    command -v npm; \
    npm --version

Thanks to https://www.theguild.nl/nvm-in-docker/ to show a more elegant way by using a login shell.

This one worked to me. Thanks @bheisig !