how to docker nodejs app code example

Example 1: simple nodejs dockerfile

FROM node:12-alpine
WORKDIR /app
COPY package.json yarn.lock ./
RUN yarn install --production
COPY . .
CMD ["node", "/app/src/index.js"]

Example 2: nodejs docker

FROM node:boron

RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app

COPY package.json /usr/src/app/
RUN npm install

COPY . /usr/src/app

EXPOSE 3000

CMD ["npm","start"]