Challenge 2: A Turbo Stream Response — Solution

# app/controllers/comments_controller.rb
def destroy
  @comment = Comment.find(params[:id])
  @comment.destroy
  respond_to do |format|
    format.turbo_stream   # renders destroy.turbo_stream.erb automatically
  end
end

# app/views/comments/destroy.turbo_stream.erb
<%= turbo_stream.remove "comment_#{@comment.id}" %>

# app/views/comments/_comment.html.erb must render each comment wrapped
# with a matching id for remove to find the right element:
<div id="comment_<%= comment.id %>">
  <p><%= comment.body %></p>
</div>

=begin
Notes:
- respond_to with format.turbo_stream follows the exact same Rails
  convention as an HTML or JSON respond_to block (rails2-5) -- Rails
  automatically looks for a view named destroy.turbo_stream.erb matching
  the action name, no manual template lookup required.
- turbo_stream.remove takes just a DOM element id string, unlike append
  (which also needs a partial/locals to render new content) -- remove has
  nothing to render, only an element to take out of the page.
- The id passed to remove ("comment_#{@comment.id}") must match the id the
  comment partial actually rendered with on the page, or Turbo has nothing
  to find and the remove silently does nothing.
- @comment.destroy happens before the turbo_stream response is rendered,
  so by the time the client removes the element from the DOM, the
  corresponding database row is already gone too.
=end