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David Teren
David Teren

Posted on • Edited on

Getting started with Rails 6.1, TailwindCSS JIT, Webpacker & PostCSS 8

This is my first post here and we are going to look at getting TailwindCSS with the awesome JIT (just in time) compilation setup in Rails 6.1 app via Webpacker and using PostCSS 8.0

Create a new Rails app

rails new tails_on_rails
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In your Gemfile update webpacker

# Replace
gem 'webpacker', '~> 5.0'

# With
gem 'webpacker', '~> 5.4.0'
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Run bundler

bundle
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Remove the default webpacker

yarn remove @rails/webpacker
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Add the required version of Webpacker and other dependancies

yarn add @rails/webpacker@5.4.0 @fullhuman/postcss-purgecss@^4.0.3 postcss@^8.2.10 postcss-loader@^4.0.3 sass@^1.32.7 autoprefixer@^10.2.6
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Your package.json should look something like this.

{
  "name": "tails-on-rails",
  "private": true,
  "dependencies": {
     "@fullhuman/postcss-purgecss": "^4.0.3",
     "@rails/actioncable": "^6.0.0",
     "@rails/activestorage": "^6.0.0",
     "@rails/ujs": "^6.0.0",
     "@rails/webpacker": "5.4.0",
     "postcss": "^8.2.10",
     "postcss-loader": "^4.0.3",
     "sass": "^1.32.7",
     "turbolinks": "^5.2.0",
     "webpack": "^4.46.0",
     "webpack-cli": "^3.3.12"
    },
  "version": "0.1.0",
  "devDependencies": {
    "webpack-dev-server": "^3.11.2"
 }
}
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Install TailwindsCSS and the official plugins.

yarn add tailwindcss @tailwindcss/forms @tailwindcss/typography @tailwindcss/aspect-ratio @tailwindcss/typography @tailwindcss/line-clamp
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Your package.json should look something like this.

{
  "name": "tails-on-rails",
  "private": true,
  "dependencies": {
    "@fullhuman/postcss-purgecss": "^4.0.3",
    "@rails/actioncable": "^6.0.0",
    "@rails/activestorage": "^6.0.0",
    "@rails/ujs": "^6.0.0",
    "@rails/webpacker": "5.4.0",
    "@tailwindcss/aspect-ratio": "^0.2.1",
    "@tailwindcss/forms": "^0.3.3",
    "@tailwindcss/typography": "^0.4.1",
    "postcss": "^8.2.10",
    "postcss-loader": "^4.0.3",
    "sass": "^1.32.7",
    "tailwindcss": "^2.1.4",
    "turbolinks": "^5.2.0",
    "webpack": "^4.46.0",
    "webpack-cli": "^3.3.12"
  },
  "version": "0.1.0",
  "devDependencies": {
    "webpack-dev-server": "^3.11.2"
  }
}
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Create the custom CSS file.

mkdir app/javascript/stylesheets && touch app/javascript/stylesheets/application.scss

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In app/javascript/stylesheets/application.scss add the following.

@import "tailwindcss/base";

@import "tailwindcss/components";

@import "tailwindcss/utilities";
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While we are on here we will add a custom component to validate that the @apply directive works.

Add the following to app/javascript/stylesheets/application.scss

.btn {
  @apply px-4 py-2 bg-blue-600 text-white rounded; 
}
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Your application.scss should look something like this.

@import "tailwindcss/base";

@import "tailwindcss/components";

.btn {
  @apply px-4 py-2 bg-blue-600 text-white rounded; 
}

@import "tailwindcss/utilities";
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In app/javascript/packs/application.js add the following;

import "stylesheets/application.scss"
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Your application.js should look something like this

import Rails from "@rails/ujs"
import Turbolinks from "turbolinks"
import * as ActiveStorage from "@rails/activestorage"
import "channels"
import "stylesheets/application.scss"

Rails.start()
Turbolinks.start()
ActiveStorage.start()
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In the app root file postcss.config.js require TailwindCSS

require('tailwindcss'),
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Your postcss.config.js should look something like this.

module.exports = {
  plugins: [
    require('tailwindcss'),
    require('postcss-import'),
    require('postcss-flexbugs-fixes'),
    require('postcss-preset-env')({
      autoprefixer: {
        flexbox: 'no-2009'
      },
      stage: 3
    })
  ]
}
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Add the following to your app/views/layouts/application.html.erb

<link rel="stylesheet" href="https://rsms.me/inter/inter.css">

<%= stylesheet_pack_tag 'application', 'data-turbolinks-track': 'reload' %>
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Your application.html.erb should look something like this.

<!DOCTYPE html>
<html>
  <head>
    <title>TailsOnRails</title>
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <%= csrf_meta_tags %>
    <%= csp_meta_tag %>

    <link rel="stylesheet" href="https://rsms.me/inter/inter.css">

    <%= stylesheet_pack_tag 'application', 'data-turbolinks-track': 'reload' %>
    <%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' %>
    <%= javascript_pack_tag 'application', 'data-turbolinks-track': 'reload' %>
  </head>

  <body>
    <%= yield %>
  </body>
</html>
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Scaffold the full TailwindCSS tailwind.config.js

npx tailwindcss init --full
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The above will generate a large configurable TailwindCSS file.

Add the TailwindCSS plug-ins to tailwind.config.js (right at the bottom of the file in the plugins: [] node.

plugins: [
  require('@tailwindcss/typography'),
  require('@tailwindcss/forms'),
  require('@tailwindcss/line-clamp'),
  require('@tailwindcss/aspect-ratio'),
]
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Add the Inter font to the fontFamily node in tailwind.config.js

fontFamily: {
  sans: [
    'Inter var',
       ...
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Enable JIT - just in time compilation at the top of the tailwind.config.js file

module.exports = {
  mode: 'jit',
  purge: [],
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Configure the purge option in the tailwind.config.js file

purge: {
enabled: ["production", "staging"].includes(process.env.NODE_ENV),
content: [
  './app/views/**/*.html.erb',
  './app/helpers/**/*.rb',
  './app/javascript/**/*.js',
],
},

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Your tailwind.config.js should look something like this.

const colors = require('tailwindcss/colors')

module.exports = {
  mode: 'jit',
  purge: {
    enabled: ["production", "staging"].includes(process.env.NODE_ENV),
    content: [
      './**/*.html.erb',
      './app/helpers/**/*.rb',
      './app/javascript/**/*.js',
    ],
  },
  presets: [],
  darkMode: false, // or 'media' or 'class'
  theme: {
    screens: {
      sm: '640px',
      md: '768px',
      lg: '1024px',
      xl: '1280px',
      '2xl': '1536px',
    },
    colors: {
      transparent: 'transparent',
      current: 'currentColor',

      // content removed ....

    flexGrow: {
      0: '0',
      DEFAULT: '1',
    },
    flexShrink: {
      0: '0',
      DEFAULT: '1',
    },
    fontFamily: {
      sans: [
        'Inter var',
        'ui-sans-serif',
        'system-ui',
        '-apple-system',
        'BlinkMacSystemFont',
        '"Segoe UI"',
        'Roboto',
        '"Helvetica Neue"',
        'Arial',
        '"Noto Sans"',
        'sans-serif',
        '"Apple Color Emoji"',
        '"Segoe UI Emoji"',
        '"Segoe UI Symbol"',
        '"Noto Color Emoji"',
      ],
      serif: ['ui-serif', 'Georgia', 'Cambria', '"Times New Roman"', 'Times', 'serif'],
      mono: [
        'ui-monospace',
        'SFMono-Regular',
        'Menlo',

      // content removed ....

    zIndex: ['responsive', 'focus-within', 'focus'],
  },
  plugins: [
    require('@tailwindcss/typography'),
    require('@tailwindcss/forms'),
    require('@tailwindcss/line-clamp'),
    require('@tailwindcss/aspect-ratio'),],
}
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In the babel.config.js file set the following

...
'@babel/plugin-transform-runtime',
{
  helpers: false,
  regenerator: true,
  corejs: false
}
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And add the following to babel.config.js

['@babel/plugin-proposal-private-methods', { loose: true }]
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Your babel.config.js should look something like this

module.exports = function (api) {
  var validEnv = ['development', 'test', 'production']
  var currentEnv = api.env()
  var isDevelopmentEnv = api.env('development')
  var isProductionEnv = api.env('production')
  var isTestEnv = api.env('test')

  if (!validEnv.includes(currentEnv)) {
    throw new Error(
      'Please specify a valid `NODE_ENV` or ' +
        '`BABEL_ENV` environment variables. Valid values are "development", ' +
        '"test", and "production". Instead, received: ' +
        JSON.stringify(currentEnv) +
        '.'
    )
  }

  return {
    presets: [
      isTestEnv && [
        '@babel/preset-env',
        {
          targets: {
            node: 'current'
          }
        }
      ],
      (isProductionEnv || isDevelopmentEnv) && [
        '@babel/preset-env',
        {
          forceAllTransforms: true,
          useBuiltIns: 'entry',
          corejs: 3,
          modules: false,
          exclude: ['transform-typeof-symbol']
        }
      ]
    ].filter(Boolean),
    plugins: [
      'babel-plugin-macros',
      '@babel/plugin-syntax-dynamic-import',
      isTestEnv && 'babel-plugin-dynamic-import-node',
      '@babel/plugin-transform-destructuring',
      [
        '@babel/plugin-proposal-class-properties',
        {
          loose: true
        }
      ],
      [
        '@babel/plugin-proposal-object-rest-spread',
        {
          useBuiltIns: true
        }
      ],
      [
        '@babel/plugin-transform-runtime',
        {
          helpers: false,
          regenerator: true,
          corejs: false
        }
      ],
      [
        '@babel/plugin-transform-regenerator',
        {
          async: false
        }
      ],
      ['@babel/plugin-proposal-private-methods', { loose: true }]
    ].filter(Boolean)
  }
}
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For Webpacker to work with this version of Postcss we need to tell it to use the loader.
In config/webpack/environment.js add the following. Just insert it between the two existing lines.

// Get the actual sass-loader config
const sassLoader = environment.loaders.get('sass')
const sassLoaderConfig = sassLoader.use.find(function (element) {
return element.loader == 'sass-loader'
})

// Use Dart-implementation of Sass (default is node-sass)
const options = sassLoaderConfig.options
options.implementation = require('sass')

function hotfixPostcssLoaderConfig (subloader) {
  const subloaderName = subloader.loader
  if (subloaderName === 'postcss-loader') {
    subloader.options.postcssOptions = subloader.options.config
    delete subloader.options.config
  }
}

environment.loaders.keys().forEach(loaderName => {
  const loader = environment.loaders.get(loaderName)
  loader.use.forEach(hotfixPostcssLoaderConfig)
})
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Your environment.js should look something like this.

const {environment} = require('@rails/webpacker')

// Get the actual sass-loader config
const sassLoader = environment.loaders.get('sass')
const sassLoaderConfig = sassLoader.use.find(function (element) {
return element.loader == 'sass-loader'
})

// Use Dart-implementation of Sass (default is node-sass)
const options = sassLoaderConfig.options
options.implementation = require('sass')

function hotfixPostcssLoaderConfig(subloader) {
  const subloaderName = subloader.loader
  if (subloaderName === 'postcss-loader') {
    subloader.options.postcssOptions = subloader.options.config
    delete subloader.options.config
  }
}

environment.loaders.keys().forEach(loaderName => {
const loader = environment.loaders.get(loaderName)
loader.use.forEach(hotfixPostcssLoaderConfig)
})

module.exports = environment
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Let's test this setup

rails g controller Home index 
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Add the following to app/views/home/index.html.erb

<div class="font-sans bg-white h-screen flex flex-col w-full">
  <div class="h-screen bg-gradient-to-r from-green-400 to-blue-500">
    <div class="px-4 py-48">
     <div class="relative w-full text-center">
       <h1 class="animate-pulse font-bold text-gray-200 text-2xl mb-6">
        Your TailwindCSS setup is working if this pulses...
       </h1>
    </div>
   </div>
  </div>
</div>
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Add the root path to point at the above /home/index in config/routes.rb

root 'home#index'
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In one terminal run bin/webpack-dev-server
And in another run rails s

⚠️ Do not try running webpack-dev-server without the bin/ prefix as it's likely it will fail to compile.

You should see this

To test the @apply directive replace the following from app/views/home/index.html.erb with class="pulsing-text"

class="animate-pulse font-bold text-gray-200 text-2xl mb-6"
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and in app/javascript/stylesheets/application.scss add the following

.pulsing-text {
@apply animate-pulse font-bold text-gray-200 text-2xl mb-6;
}
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Your applications.scss should look like something like this.

@import "tailwindcss/base";

@import "tailwindcss/components";

.pulsing-text {
@apply animate-pulse font-bold text-gray-200 text-2xl mb-6;
}

@import "tailwindcss/utilities";
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When you refresh you home page in the browser you should still see this.

GitHub Repo

Top comments (21)

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curting profile image
Oliver Curting

Hi David! Thanks a bunch for your walkthrough. Very helpful!
That being said, when running bin/webpack-dev-server it keeps re-compiling every second. As a result the page keeps refreshing. Any thoughts on how to fix that?

All the best,
Oliver

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keijsvog profile image
Koen Eijsvogels

Hi Oliver,

I followed above instructions and got the same issue as you did.
I changed the tailwind.config.js a little bit: I did not use ./**/*.html.erb in the purge section but ./app/**/*.html.erb. This solved for me the issue of the recompiling.

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davidteren profile image
David Teren

Thanks for that. It was pointed out to me by someone else as well and came here to change it and saw your comment now only. 🤦‍♂️

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davidteren profile image
David Teren

Hey Oliver, thanks so much for the feedback.
What version of Ruby are you running?

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alistairtweed profile image
Alistair Tweed

I'm experiencing the same issue on Ruby 2.7.3.

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scotti_jack profile image
Jack Scotti

same issue on Ruby 3.0.1

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xertrov profile image
Max Kaye • Edited

Edit: I think I was wrong below. Here's what worked: try setting compile: false in webpacker.yml and commenting mode: 'jit', in tailwind.config.js. I can run bin/webpack-dev-server, rails s, and guard at the same time now without issue or compile-refresh loops.


This started happening to me after I got tailwind working. Are you running some live-reloading tool? (e.g., I was running bundle exec guard.) If so, try not running that. bin/webpack-dev-server handles livereloading when running, it seems.

NB: webpack-dev-server would almost always compile things twice for me (now) but stops after that (until I make another change).

I also noticed that commenting mode: 'jit', in tailwind.config.js seemed to fix it too, before I stopped running guard.

You can also just not run bin/webpack-dev-server -- rails s will still compile stuff for you and then you can have bundle exec guard in the bg if you prefer that.

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caioabe profile image
Caio Abe

Great tutorial!

I'd like to point 2 improvements tough:

Typo in:

<!-- missing ">" -->
<link rel="stylesheet" href="https://rsms.me/inter/inter.css"
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Since I wasn't used to rails with webpack, had to figure out this:

# run this after updating the webpack in gemfile
bundle exec rake webpacker:install
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davidteren profile image
David Teren

Hi Caio, thanks for that. Fixed now.

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francescok profile image
Francesco Kirchhoff

One recommendation for an edit:
Following on a fresh Rails app, it looks like webpack-cli needs to be at at least 4.3.0 or it will throw an error. (TypeError: Class constructor ServeCommand cannot be invoked without 'new' etc.)

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storrence88 profile image
Steven Torrence

I had this same issue however upgrading webpack-cli to 4.3.0 didn't work for me. I had to upgrade to 4.7.2 in order for it to run. Not sure why?

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frogfangio profile image
Albert Anstett

Great article, kudos !
I found one typo and since you did such a great job with this article, I would be glad to help by pointing to it: the path to config/webpacker/environment.js should be config/webpack/environment.js (webpack, not webpacker).

I also have a question: in file app/views/layouts/application.html.erb, the line
<%= stylesheet_pack_tag 'application', 'data-turbolinks-track': 'reload' %>
is duplicate at lines 11 and 13. Is this done on purpose ?

Cheers and thanks again.

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davidteren profile image
David Teren • Edited

Thanks for the kudos.
Fixed the typo.

I'm not sure I follow your comment re the duplicate line. The three pack and link tags each have very distinct purposes.
If I'm missing something, please feel free to point it out.

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davidteren profile image
David Teren

Fixed. Thanks.

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msojka profile image
Martin Sojka

Awesome! Works like a charm. Thanks @davidteren

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stephaneliu profile image
Stephane Liu

Thank you so much for writing this article. Fantastic!

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mzrnsh profile image
Giorgi Mez

Awesome guide, very easy to follow. Thank you, David

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franciscomunozs profile image
Francisco Muñoz

Hi David, great tutorial, thanks a lot, it's a chance to use this with Alpine.js?
been trying for a while but I can't make it work. thanks a lot.

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davidteren profile image
David Teren

Hi Fransico, I've previously set that up and written about it here Tailwind UI, Tailwind CSS, AlpineJS & Inter Typeface for Ruby on Rails.

Let me know if that does not work for you and I'll write it up.

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franciscomunozs profile image
Francisco Muñoz

Oh, sorry, I didn't see your reply, I'm deeply sorry.
Thanks for your answer. For a long time, I use that tutorial, until Tailwind UI get the 2.0 version update, after that, I can't get AlpineJS working on my curret RoR setup.

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kdiogenes profile image
Kadu Diógenes

Hey, David! Thanks a lot for taking the time to write this, really helpful!