Docker and private packages with .npmrc

I am using a .npmrc file to configure a private repo (font-awesome-pro).

It works well without docker.

But with docker, the npm install fails:

npm ERR! code E401
npm ERR! 404 401 Unauthorized: @fortawesome/fontawesome-pro-light@https://npm.fontawesome.com/7D46BEC2-1565-40B5-B5FC-D40C724E60C6/@fortawesome/fontawesome-pro-light/-/fontawesome-pro-light-5.0.12.tgz

I have read the doc from NPM : Docker and private packages, but I don't know how to apply it with docker-compose.yml and I not sure passing variables is the solution (?). Is it possible that the .npmrc file is not read during installation inside the docker instance ? Am I missing something ?

Here is my docker-compose.yaml :

version: '2.1'
services:
  app:
    image: node:8.9.4
    # restart: always
    container_name: jc-vc
    environment:
      - APP_ENV=${JC_ENV:-dev}
      - HOST=0.0.0.0
      - BASE_URL=${JC_BASE_URL}
      - BROWSER_BASE_URL=${JC_BROWSER_BASE_URL}
    working_dir: /usr/src/app
    volumes:
      - ${DOCKER_PATH}/jc/vc/app:/usr/src/app
    command: npm install
    # command: npm run dev
    # command: npm run lintfix
    # command: npm run build
    # command: npm start
    expose:
      - 3000
      
  nginx:
    image: nginx
    logging:
      driver: none
    # restart: always
    volumes:
      - ${DOCKER_PATH}/jc/vc/nginx/www:/usr/share/nginx/html
      - ${DOCKER_PATH}/jc/vc/nginx/default.${JC_ENV:-dev}.conf:/etc/nginx/nginx.conf
      - ${DOCKER_PATH}/jc/vc/nginx/.htpasswd:/etc/nginx/.htpasswd
      - ${DOCKER_PATH}/jc/letsencrypt:/etc/letsencrypt
    container_name: jc-nginx-vc
    depends_on:
      - app
    ports:
      - ${PORT_80:-4020}:${PORT_80:-4020}
      - ${PORT_443:-4021}:${PORT_443:-4021}

and my .npmrc (with replaced token) :

@fortawesome:registry=https://npm.fontawesome.com/
//npm.fontawesome.com/:_authToken=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX

package-lock.json needs to be re-generate with the new .npmrc file. Delete it package-lock.json and recreate it with npm install then redeploy the image.