How to use Node.js with Docker?

Firstly, install Docker and Node.js on your machine. Next, follow these steps:

1. Initialize a Node.js application: Start a new Node.js application, if you haven’t done so yet. You can do this by creating a new directory and running `npm init -y` to automatically create a new `package.json` file.

1. Create a Dockerfile: Create a new file in your application directory called `Dockerfile`.

Here is an example Dockerfile for a Node.js application:

```

This is your Dockerfile
Start from a base image
FROM node:14

Set the working directory
WORKDIR /usr/src/app

Copy package.json and package-lock.json
COPY package*.json ./

Install dependencies
RUN npm install

Copy local code to the container’s workspace.
COPY . .

Set the API’s port number
EXPOSE 8080

Define the command to run your app
CMD [ “node”, “index.js” ]
```

1. Build the Docker Image: In the same directory as your Dockerfile, run the following command to create a Docker image. Replace `my-app` with the name you wish to give your image.

`docker build -t my-app .`

1. Run Docker Container: ‘my-app’ is the name of the image and 8080 is the port to be exposed. Use the following command to run your container:

`docker run -p 8080:8080 -d my-app`

1. Check running Docker Containers:

`docker ps`

Now, if you visit localhost at specified port (in this case, 8080), you should see your app running.