Which Node version? Docker!

In a take-home tech challenge, I was asked to develop a webapp and one of the prerequisites was that they might not know which version of Node I was using. My solution at that point was straighforward: I described the version in the README.md file. 😅 Although that's not a bad answer, the interviewer was aiming at another point...

CONTAINERS!

I already had some experience running database containers from Docker Hub, but had not yet done this for a front-end code. Is not big of a deal after all, so let's see how it works.

First things first - Project Setup

Since this project uses Vite we have to add some settings inside the vite.config.js file. You can skip this step if not using it. The react and tsconfigPaths should be already there if is a React Typescript app.

import { defineConfig } from 'vitest/config'
import react from '@vitejs/plugin-react'
import tsconfigPaths from 'vite-tsconfig-paths'

export default defineConfig({
  plugins: [react(), tsconfigPaths()],
  server: {
    host: true,
    strictPort: true,
    port: 8000, // This is the port which we will use in docker
    watch: {
      // when using windows and hot reload doesn't work
      usePolling: true,
    },
  },
})

Then add a .dockerignore file to the root of your project (next to package.json). This works similar to .gitignore, which will prevent docker from copying anything that is mentioned there. This is how it should be:

node_modules

Finally, create the dockerfile again on the root of your project.

FROM node:18-alpine

WORKDIR /srv/app

EXPOSE 8000

CMD ["/bin/sh"]

Create a Docker Image

Now, open your terminal and type this command

docker build -t vite-image .

You can notice that we pass the flag -t, which stands for tag or the name of this image that we supply right after, in this case, vite-image.

Create a container from this image

Finally, we can create the container with the RUN command

docker run -it --name vite_docker -p 8000:8000 --mount type=bind,source=$(pwd),target=/srv/app vite-image

The -it flags are used to keep STDIN open and to allocate a pseudo-tty respectvelly. This enables to access the terminal inside the container when it's running. Next we name the container with --name, in this case vite_docker.

We also pass -p to set the ports as host:app. The first one is where the container will be opened and the second is for the application.

Followed by --mount that will associate the files on our project to the directory inside the container. This allows us to modify the code and see the results instantly.

Install Dependencies and run the app

Upon completion, it will open the terminal inside the container and you can run your application with

yarn && yarn dev

You can access the output at http://localhost:8000/ Whenever you modify the code it will update in the browser. 🥳

Last Notes

It is important to understand that this container ensures that all developers have the same environment on their computers and can run the application without installing any node_modules. This container is not valid for production deployment.