Installing node and npm on a Django AWS ElasticBeanstalk

.ebextensions\deploy.config

# This specifies the deployment process on AWS ElasticBeanstalk for a Django app using npm and Postgres.
#
# The target environment should have access to a Postgres Database through environment variables.
# The environment can be setup using `eb create --database.engine=postgres`
# The necessary environment variables to access the database will be automatically defined on the
# instances of that environment.
#
# In addition, the target environment should define environment variables (django secret key ...).
# They can be manually defined using the AWS ElasticBeanstalk interface on the web.
# They can also be specified when creating the environment from command line, for example: 
# ```
# eb create --database.engine=postgres --envvars ENVVAR1=value,ENVVAR2=value
# ```
#

packages:
    yum:
        git: []
        postgresql93-devel: []

commands:
    01_node_install:
        cwd: /tmp
        test: '[ ! -f /usr/bin/node ] && echo "node not installed"'
        command: 'yum install -y nodejs --enablerepo=epel'
    02_npm_install:
        cwd: /tmp
        test: '[ ! -f /usr/bin/npm ] && echo "npm not installed"'
        command: 'curl -L http://npmjs.org/install.sh | sh'
    03_node_update:
        cwd: /tmp
        test: '[ ! -f /usr/bin/n ] && echo "node not updated"'
        command: 'npm install -g n && n stable'

option_settings:
    "aws:elasticbeanstalk:application:environment":
        # your settings module here
        DJANGO_SETTINGS_MODULE: "server.settings_prod" 
        
        # add the path to the root of your django app
        # note that this is the path on the target machine
        # EB will deploy your application in /opt/python/current on the target machines
        PYTHONPATH: "/opt/python/current/app/server:$PYTHONPATH"
        
    "aws:elasticbeanstalk:container:python":
        # path to your wsgi.py file from the root folder of your application
        WSGIPath: server/server/wsgi.py
        NumProcesses: 3 
        NumThreads: 20
        
    "aws:elasticbeanstalk:container:python:staticfiles":
        "/static/": "www/static/"

# These commands will be run just before the application is started
container_commands:
    01_migrate:
        command: 'python server/manage.py migrate --noinput'
        leader_only: true
        
    # You can create a "createadmin" command to create a super user automatically
    # You can use environment variables to define the credentials of the super user
    # If you don't use a createadmin command, delete this command.
    02_createadmin:
        command: 'python server/manage.py createadmin'
        leader_only: true
    
    # You can define a build script in packages.json (using gulp, grunt...) to build your client side files
    03_npm_build:
        command: 'npm install && npm run build'
        
    04_collectstatic:
        command: 'python server/manage.py collectstatic --noinput'

@systemTetra2 As @HCNick pointed out, Node isn't available anymore through EPEL repo. What worked for me is, I created a post deploy hook (bash script) in .platform/hooks/postdeploy and installed Node through nodesource.com:

# Install NPM (if it doesn't exist)
if ! command -v npm &> /dev/null
then
  curl -fsSL https://rpm.nodesource.com/setup_14.x | sudo bash -
  sudo yum install nodejs -y
fi

# Install dependencies
npm install

# Compile assets
npm run build

This is for Node 14, I haven't tested it for latest version.