How to Change Page Titles Dynamically in Rails

Environment

macOS Mojave 10.14.4
Rails 5.2.2
ruby 2.6.1

Goal

Dynamically change page titles

A common approach to changing page titles dynamically: when users navigate to the top page, show only the domain name; when they go to the login page, show something like “login | domain name”.

For detailed explanations, refer to the Rails Tutorial.

You could write the title directly in application.html.erb, but it’s better to define it in a helper for easier fine-tuning later.

# app/helpers/application_helper.rb
module ApplicationHelper
  # Returns the full title for each page
  def full_title(page_title = '')
    base_title = "shou2017.com"
    if page_title.empty?
      base_title
    else
      page_title + " | " + base_title
    end
  end
end

Then, make the full_title helper available in application.html.erb.

<!-- app/views/layouts/application.html.erb -->
<!DOCTYPE html>
<html>
  <head>
    <title><%= full_title(yield(:title)) %></title>

Use provide to set individual page titles.

<% provide(:title,  " Login") %>
<h1>Login</h1>