how to use dockerignore file with node js app code example

Example 1: dockerfile for nodejs

# Choose the Image which has Node installed already
FROM node:alpine

# COPY all the files from Current Directory into the Container
COPY ./ ./

# Install the Project Dependencies like Express Framework
RUN npm install

# Tell that this image is going to Open a Port 
EXPOSE 8080

# Default Command to launch the Application
CMD ["npm", "start"]

Example 2: docker run npm install express syntax

FROM node:12

# Create app directory
WORKDIR /usr/src/app

# Install app dependencies
# A wildcard is used to ensure both package.json AND package-lock.json are copied
# where available (npm@5+)
COPY package*.json ./

RUN npm install
# If you are building your code for production
# RUN npm ci --only=production

# Bundle app source
COPY . .

EXPOSE 8080
CMD [ "node", "server.js" ]