= Node JS =

 * ref[https://nodejs.org/en/docs/guides/nodejs-docker-webapp/ here][[br]]

1. First, create a new directory where all the files would live. In this directory create a package.json file that describes your app and its dependencies: file package.json as following
{{{
{
  "name": "docker_web_app",
  "version": "1.0.0",
  "description": "Node.js on Docker",
  "author": "First Last <first.last@example.com>",
  "main": "server.js",
  "scripts": {
    "start": "node server.js"
  },
  "dependencies": {
    "express": "^4.16.1"
  }
}
}}}
With your new package.json file, run npm install. If you are using npm version 5 or later, this will generate a package-lock.json file which will be copied to your Docker image. [[br]]

2. Then, create a server.js file that defines a web app using the Express.js framework:
{{{
'use strict';

const express = require('express');

// Constants
const PORT = 8080;
const HOST = '0.0.0.0';

// App
const app = express();
app.get('/', (req, res) => {
  res.send('Hello World');
});

app.listen(PORT, HOST, () => {
  console.log(`Running on http://${HOST}:${PORT}`);
});
}}}

3.create Dockerfile with following content
{{{
FROM node:16

# 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" ]
}}}

4. Create a .dockerignore file in the same directory as your Dockerfile with following content:
{{{
node_modules
npm-debug.log
}}}
This will prevent your local modules and debug logs from being copied onto your Docker image and possibly overwriting modules installed within your image.