Last week, I deployed a single-page web application on built with the Parcel bundler. Here’s how!


The files of my web application started off looking like this:

├── img/
├── index.html
├── main.js
├── package.json
└── styles.css

A single index.html entry point, with logic in main.js and styles provided by styles.css. There are some PNGs in img/ used for favicons. They’re all authored in a human-readable way—that is, with whitespace, and meaningful variable names.

Let’s bundle this with Parcel!

First, install parcel-bundler:

npm install parcel-bundler --save-dev

Then, build index.html with Parcel:

npx parcel build index.html

Next, in a new folder called dist/ you’ll see index.html and all the files included by it in dist/. But, they’ll be minified and content hashed!

With minification, index.html gets a modest 9.2% size decrease from 3.8 KiB to 3.45 KiB. However, styles.css goes from 2.7 KiB to 995 bytes, a 63.1% decrease!

Setting up package.json

I only want to commit my source code to GitHub; I don’t want to remember to build my package and push the resulting build products every time I change a single line of code (I know git pre-commit hooks exist, but… eww, no). Luckily, Now will run a build step for you before deploy!

I used Now’s official static builder. @now/static-builder will run a script specified in package.json. It expects that the results of the build will be created in a folder called dist/. It just so happens that Parcel places build output in dist/ by default!

To setup, @now/static-builder, I added the following line to the scripts key in package.json:

   "scripts": {
      "now-build": "parcel build index.html"

Notice how this is the same line as before, just minus the npx part.

The nice thing about this, is that we can test if our build works by running the following command locally:

npm run now-build

Setting up now.json

To configure the @now/static-build builder, add a line to the builds key in now.json. Luckily, now.json doesn’t tend to have a lot of configuration, so the following is a complete now.json that you can copy-paste, and it will work in your app:

  "version": 2,
  "builds": [
    { "src": "package.json", "use": "@now/static-build" }


From here, it’s up to your Now setup. I tend to push to a new branch in GitHub, and create a pull request. With Now’s GitHub Integration, this will automatically start the build and deploy it when it’s successful. I’ve added an alias to my now.json, so the latest pull request will be deployed as soon as it’s merged.

Other things

There’s an custom Now builder on npm, but I decided against using this, I’m wary of adding low star-count dependencies, ever since that event-stream incident. It turns out that using @now/static-build was fairly straightforward, so the custom package didn’t seem worth adding an extra requirement.

That’s all I got. I really like how relatively simple and painless it was to create a fast, minified, cache-friendly single-page web application with Now and Parcel. Getting a neat domain was pretty simple too! It’s bring us back to the simpler times when we’d deploy a new version of our application by uploading our PHP file via FTP to some random server. Ah, memories!