Building a Dev Server with Express and Webpack

(This post picks up where my previous post, about building a React app from scratch, left off. I recommend reading it first if you haven’t used Webpack before.)

I recently built my first React app without using the create-react-app command, and — riding a wave of JavaScript confidence from the accomplishment — I decided to dig deeper and try to build my own development server using Node.js.

My goal was to build a server that would (1) serve theindex.html page of my single-page React application and (2) hot reload (i.e., re-compile my code and refresh the browser) each time I made changes to my code.


I was able to accomplish goal #1 quickly using Express. All I had to do was install the framework:

npm i --save-dev express

Then, create a single server.js file in my project’s root directory with the following:

And lastly, run the server with Node:

node server.js

This server technically works, but it’s very tedious to use. I have to manually re-compile my project each time I start the server and anytime I make changes to my code. That is not ideal.

What I need is a way to tell Webpack to compile my project in my Node environment.

Running Webpack in Node

Bringing Webpack into my Node environment was more intuitive than I thought it would be. Webpack exports a function that takes a Webpack configuration object as its argument. This function compiles our code:

The webpack() function returns a compiler object that can be used to serve the final product. First, I’ll need to add some middleware to help:

npm i --save-dev webpack-dev-middleware

Then, import the middleware and replace the express.static call I was using before:

So now when I run node server.js, Webpack compiles my code first and then serves the generated index.html with my bundled JavaScript. I’ve checked-off goal #1. Let’s see about goal #2, adding hot reload.

Adding hot reload

To add the hot reload feature to our server, all we need to do is add another bit of middleware to our dependencies:

npm i --save-dev webpack-hot-middleware

And tell our server to use it:

Now, Webpack re-compiles my code anytime I make a change and refreshes my browser, rendering the changes.

In the end, I have an extremely bare server that hot-reloads each time I make changes. It’s usable for any development build, but there is one small problem I wasn’t able to overcome.

If you follow along and build a server identical to mine, you’ll notice that it starts listening for requests before Webpack finishes compiling the project. I tried a number of different strategies for fixing this, but couldn’t get any of them to work properly.

I ended up just using setTimeout() as a hack to delay my server while Webpack does its thing. If anyone reading this figures out how to fix this, respond to this story and let me know.



Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store