[ERROR message display] A simplified version that can be used at any time with the rails partial template.

【goal】

Display error message

【merit】

■ UX improvement ■ Improved understanding of partial templates

【Development environment】

■ Mac OS catalina ■ Ruby on Rails (5.2.4.2) ■ Virtual Box:6.1 ■ Vagrant: 2.2.7

【Implementation】

Application creation

• Touch is a command to create a file in the current directory.

mac.terminal

$ rails new error_test
$ cd error_test
$ rails g scaffold Item name:string texte:text amount:integer
$ rails db:migrate
$ cd app/views/layouts
$ touch _error_messages.html.erb

Model postscript

• Conditions for saving the DB *** Added validation = storage restrictions **

models/item.rb

class Item < ApplicationRecord
  validates :name, presence: true
  validates :text, presence: true
  validates :amount, presence: true
end

View postscript

• Partialized and improved mediocrity *** By putting it in "layputs / _error_messages.html.erb" Can be used on all models with validation !!!! **

layputs/_error_messages.html.erb

<% if model.errors.any? %>
  <div class="alert alert-warning">
    <ul>
      <% model.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
    </ul>
  </div>
<% end %>

※to add

Items/_form.html.erb

<%= render 'layouts/error_messages', model: f.object %>

• ** The above is not required when creating with scaffold ** Because the following code is described in the view of each _form (scaffold is super convenient)

/_form.....

<% if item.errors.any? %>
<div id="error_explanation">
  <h2><%= pluralize(item.errors.count, "error") %> prohibited this item from being saved:</h2>

  <ul>
    <% item.errors.full_messages.each do |message| %>
    <li><%= message %></li>
    <% end %>
  </ul>
</div>
<% end %>

• The original scaffold

• Partial

that's all. as you like! !! !!

[I want to read it together]

■ Regarding error messages https://qiita.com/ryuuuuuuuuuu/items/1a1e53d062bff774d88a

■hidden_field https://qiita.com/tanaka-yu3/items/0d454c5ef80f8267f09d

■ Application creation https://qiita.com/tanaka-yu3/items/3fe1ed2852c6513d3583