railsで「rails-ujs」を使った非同期通信

Rails.application.routes.draw do
  get '/example', to: 'example#index'
  post '/example/greet', to: 'example#greet'
end

class ExampleController < ApplicationController
  layout "application"

  def index
    @message = "上のボタンを押すとメッセージが変わるよ！"
  end

  def greet
    @message= params[:greet]
  end
end

h1 rails-ujs使用例

/ link_toで実装
= link_to example_greet_path(greet: "こんにちは"), method: :post, remote: true do
  p こんにちは

/ form_withで実装
= form_with url: example_greet_path, remote: true do
  = hidden_field_tag :greet, "こんばんは"
  = submit_tag "こんばんは"

#js-greet
  = render partial: "greet"

p = @message

document.querySelector("#js-greet").innerHTML = "<%= j(render partial: "greet") %>"