How to setup Tailwind with PurgeCSS and PostCSS

I recently set out to move my blog CSS to Tailwind.

Tailwind is an interesting framework because instead of providing a set of widgets like Bootstrap or others, it provides utilities.

I find it resonates a lot with how I work with HTML.

I introduced how I use Tailwind with Vue in a previous post, but without a build tool in place already, it can be hard to get the correct setup right, and I decided to write this blog post even just for me to remember later on 🙃

In this post I explain how to use Tailwind with any kind of project.

Install Tailwind

First step is to install Tailwind, using npm or yarn:

# Using npm
npm install tailwindcss --save-dev

# Using Yarn
yarn add tailwindcss --dev

Create the configuration file

Next, use the Tailwind command that is provided to create a configuration file.

./node_modules/.bin/tailwind init tailwind.js

This will create a tailwind.js file in the root of your project, adding the basic Tailwind configuration. The file is very long, and I won’t paste it here, but it contains lots of presets that will be very useful later.

Configure PostCSS

Now you need to tweak the PostCSS configuration to make sure Tailwind runs. Add:

const tailwindcss = require('tailwindcss')

module.exports = {
  "plugins": [
    require('tailwindcss')('tailwind.js'),
    require('autoprefixer')(),
  ]
}

to your postcss.config.js. Create one if it does not exist.

Create the Tailwind CSS file

Now create a CSS file where you want, like in src/tailwind.css and add

@tailwind preflight;
@tailwind components;
@tailwind utilities;

Create the build command

Now open your package.json file, and add a scripts section if you don’t have it:

  "scripts": {
    "build:css": "postcss src/tailwind.css -o static/dist/tailwind.css"
  }

Build Tailwind

Now from the command line run yarn build:css will build the final CSS file.

The resulting file is in static/dist/tailwind.css (you can change the location in the above command).

Trim the file size

If you check, the resulting file is huge. Even if you don’t use any Tailwind class in your HTML, all of the framework is included by default, because that’s the default configuration in the tailwind.js file.

They decided to include all, to avoid people missing things. It’s a design choice. We now need to remove stuff.

I also want to remove all comments from the CSS and make it as small as possible. cssnano is what we’re looking for.

We can automate this stuff! First, install those utilities:

npm i -D cssnano
npm i -D @fullhuman/postcss-purgecss

Then we create a PostCSS configuration file

const tailwindcss = require('tailwindcss')
const purgecss = require('@fullhuman/postcss-purgecss')
const cssnano = require('cssnano')
const autoprefixer = require('autoprefixer')

module.exports = {
  plugins: [
    tailwindcss('./tailwind.js'),
    cssnano({
      preset: 'default',
    }),
    purgecss({
      content: ['./layouts/**/*.html']
    }),
    autoprefixer
  ]
}

Automatically regenerate the CSS upon file changes

In my case I have a folder called layouts which contains all the HTML files that build up my site.

It’s the same folder I reference in the purgecss configuration above.

Every time I change something in there, I want to regenerate the CSS, and trigger the purge and minification I set up.

How to do this?

Install the watch npm package:

npm install watch

and add the watch script to your package.json file. You already had build:css from before, we just add a script that watches the layouts folder and runs build:css upon every change:

"scripts": {
  "build:css": "postcss src/tailwind.css -o static/dist/tailwind.css",
  "watch": "watch 'npm run build:css' ./layouts"
}

Now run npm run watch or yarn watch and you should be good to go!