Modern Front-end Development for Rails/

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Using Data in Stimulus

Using Data in Stimulus

Learn to use data with Stimulus in this lesson.

We'll cover the following...

With async, await, and fetch in our toolbox, we can get our Stimulus controller to contact the server directly to get the information about which concerts are sold out.

Sold-out concerts controller

On the Rails side, I’d like to set this up as its own route by adding a new singular resource to the routes.rb file:

#---
# Excerpted from "Modern Front-End Development for Rails",
# published by The Pragmatic Bookshelf.
# Copyrights apply to this code. It may not be used to create training material,
# courses, books, articles, and the like. Contact us if you are in doubt.
# We make no guarantees that this code is fit for any purpose.
# Visit http://www.pragmaticprogrammer.com/titles/nrclient for more book information.
#---
Rails.application.routes.draw do 
  resource :schedule
  resources :ticket_orders
  resources :tickets
  resources :gigs
  resources :concerts
  resources :bands
  resources :venues
  resource :sold_out_concerts, only: :show 
  devise_for :users
  
  root to: "schedules#show"
end

This lets us put the API code in a new controller, which is good both from a conceptual standpoint—it’s a completely different kind of request—and from a practical standpoint—as its own route, it might be easier to separate into a designated server later on.

The controller is similar to what were were sending earlier in this chapter via Gon:

#---
# Excerpted from "Modern Front-End Development for Rails",
# published by The Pragmatic Bookshelf.
# Copyrights apply to this code. It may not be used to create training material,
# courses, books, articles, and the like. Contact us if you are in doubt.
# We make no guarantees that this code is fit for any purpose.
# Visit http://www.pragmaticprogrammer.com/titles/nrclient for more book information.
#---
class SoldOutConcertsController < ApplicationController
  def show
    concerts = Concert.includes(:venue, gigs: :band).all
    sold_out_concert_ids = concerts.select(&:sold_out?).map(&:id)
    render(json: {sold_out_concert_ids: sold_out_concert_ids})
  end
end

We’re returning a JSON file to be parsed on ...