Following this article from Thoughtbot, this demo application utilizes an out-of-the-box Rails installation to build a collapsible search-as-you-type text box that expands to show its results in-line while searching, supports keyboard navigation and selection, and only submits requests to our server when there is a search term.
The source article states that code samples contained in it "omit the majority of the application's setup." I will attempt to cover some of the missing pieces here.
After generating a Message scaffold, running bin/rails db:migrate and declaring root 'searches#home' in routes.rb enables us to start up the rails server and see the application in action. Remember to add a home action to the SearchesController as well as the corresponding view.
This was a tricky step to navigate because Rails out-of-the-box comes with SQLite and not PostgreSQL, which means that ILIKE expressions are not available. Rather than changing the database driver, I opted to use the LIKE expression, which is case-insensitive in SQLite. The resulting scope is as follows:
# app/models/message.rb
class Message < ApplicationRecord
scope :containing, -> (query) { where("body LIKE ?", "%#{query}%") }
end