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Conway's Game of Life, with Ruby on Rails, Stimulus.js and Turbolinks
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Conway's Game of Life

This is a variation of the Game of Life, implemented with Ruby on Rails, where each generation is requested via AJAX and gets entirely computed and rendered server-side so that the browser only needs to replace the grid in the DOM. On top I sprinkled some Stimulus.js to add just enough behavior to make it shine. If you look very closely you will also see Turbolinks in action. Oh... and by the way: the Asset Pipeline was exchanged for a complete Webpack setup, so no Sprockets have been harmed in delivering JavaScript and Stylesheets.

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Setup the application

  1. Clone this repo with git clone
  2. Run bundle install
  3. Run yarn install
  4. Create a database with rails db:setup
  5. Run the rails server rails s -p 9000 (because it will be so turbo)
  6. Navigate your browser to localhost:9000

Since this is not a setup tutorial and if for some reason something does "not work", please refer to the amazingly detailed rails guides.

Some notes on what I did (the webpack way):

I created a fresh project with:

rails _5.2.1.rc1_ new turbo-game-of-life --webpack=stimulus -JSCT -d sqlite3

(For the heroku deployment I switched to postgresql, but at the moment the app does not need a database...)

-JSCT expands to:

  • --skip-javascript
  • --skip-sprockets
  • --skip-action-cable (for no reason I kept action-mailer and active-storage...)
  • --skip-test (😱) => I prefer to setup rspec 😉

if you want to disable sprockets on an exsisting application you need to select the frameworks manually in config/application.rb:

require "rails"
# Pick the frameworks you want:
require "active_model/railtie"
require "active_job/railtie"
require "active_record/railtie"
require "active_storage/engine"
require "action_controller/railtie"
require "action_mailer/railtie"
require "action_view/railtie"
# require "sprockets/railtie"

Also check all the environment and initializer files for any hidden config.assets settings ;)

This brought me in the position to start moving away from the asset pipeline and go all-in webpack:

# config/application.rb
# if you use rails generators set:
config.generators.assets = false

And then rm -rf app/assets 👋.

I renamed the webpack folder from ambiguous javascript to webpack mv app/javascript app/webpack, but the folder structure is totally up to you (but this requires to change the source_path in webpacker.yml to app/webpack).

Remove the line with stylesheet_link_tag in app/views/layouts/application.html.erb

<%= stylesheet_pack_tag 'stylesheets', 'data-turbolinks-track': 'reload' %>
<%= javascript_pack_tag 'application', 'data-turbolinks-track': 'reload', defer: true %>

The webpack/packs/stylesheets.scss just imports bootstrap

@import '../src/stylesheets/variables';
@import '../src/stylesheets/bootstrap';

add src/bootstrap.scss

@import '~bootstrap/scss/bootstrap';

Then edit the Gemfile to add the turbolinks gem for having "javascript redirect support" in the controller:

gem 'turbolinks', '~> 5'

And since there is no asset pipeline anymore I need to add rails-ujs etc to the package.json:

yarn add rails-ujs turbolinks bootstrap

In packs/application.js I replaced console.log('Hello World from Webpacker') with:

import Rails from 'rails-ujs';
import Turbolinks from 'turbolinks';
import { Application } from "stimulus"
import { definitionsFromContext } from "stimulus/webpack-helpers"

start all the things!


const application = Application.start()
const context = require.context("../src/javascript/controllers", true, /.js$/)

Now start the webpack dev server ./bin/webpack-dev-server => webpack compiles successfully


I hope that's clear. If you have any questions, don't hesistate to ask.

Until then, have a nice day! :)

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