How to install Bootstrap in Rails 6 (with Yarn and Webpacker)

TLDR version of this post >>here<<

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There are many guides and many paths to make bootstrap available in Rails 6.

Having analyzed dozens of tutorials and production applications, below seems to be the most "correct" path.

In Rails 5 you would normally use gem bootstrap that would "download" the bootstrap JS and CSS files.

As we are using webpacker in Rails 6, the right way is to install a package. Webpacker is fit to work with the "yarn package manager".

Bootstrap has an official yarn package, meaning that it can be installed with a command like yarn add bootstrap (instead of installing a gem)!

But bootstrap has some dependencies like jquery and popper.js that need to be installed too.

As well, in Rails 5 we used stylesheets in app/assets/stylesheets/application.css:

And to tell our application to use this file, in application.html.erb in Rails 5 we added the line to application.html.erb:

= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track': 'reload'

In Rails 6, we will be compiling the stylesheets inside the javascripts folder.

Let's start:

1. In the console run the command:

yarn add jquery popper.js bootstrap

it will install the yarn packages that you need to run bootstrap.

1. In the file environment.js add the following:

const { environment } = require('@rails/webpacker')
const webpack = require("webpack")
environment.plugins.append("Provide", new webpack.ProvidePlugin({
    $: 'jquery',
    jQuery: 'jquery',
    'window.jQuery': 'jquery',
    Popper: ['popper.js', 'default']
  }))
module.exports = environment

1. Create a folder app/javascript/stylesheets.

In the folder app/javascript/stylesheets create a new file application.scss:

We will be placing all the css there.

1. Make the app/javascript/stylesheets available in your application.html.erb.

application.html.erb should look like this:

= javascript_pack_tag 'application', 'data-turbolinks-track': 'reload' 
= stylesheet_pack_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' 
= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' 

Notice the stylesheet_pack_tag.

1. Finally, in application.js we add

import 'bootstrap/dist/js/bootstrap'
import 'bootstrap/dist/css/bootstrap'
require("stylesheets/application.scss")

The first 2 "import" commands add the bootstrap JS and CSS that was imported by yarn.

The last "require" makes anything that you add in app/javascript/stylesheets/application.scss compile whenever you add a change to it.

1. Now you can add a bootstrap classes like in any view:

<span class="badge badge-secondary">Thanks Yaro! It works!</span> 

and it will add a Bootstrap badge.

Hooray! Bootstrap is installed!😊

P.S. If you will be adding actiontext, it's good to place it under app/javascript/stylesheets/application.scss:

@import "./actiontext.scss";

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Relevant links

• TLDR version of this post
• see the official Bootstrap docs here
• Bootstrap yarn package

That's it 🤠

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