Vanilla Rails Hotwire

37signals Hotwire conventions beyond the official docs.

Turbo Streams

Always dom_id, never string interpolation:

<%# Wrong %>
<%= turbo_stream.replace "card_#{@card.id}" do %>

<%# Right %>
<%= turbo_stream.replace dom_id(@card) do %>
<%= turbo_stream.replace [ @card ] do %>

Prefixed dom_id for granular updates:

dom_id(@card)                # "card_abc123"
dom_id(@card, :header)       # "header_card_abc123"
dom_id(@card, :status_badge) # "status_badge_card_abc123"

Always method: :morph for replacements (avoids layout shift, preserves scroll):

<%= turbo_stream.replace dom_id(@card, :status), method: :morph do %>
  <%= render "cards/status", card: @card %>
<% end %>

Morph for updates. append/prepend for new items. remove for deletions.

Stimulus Controllers

One purpose per controller. Split large controllers.

Private methods with # prefix — only methods called from data-action are public:

export default class extends Controller {
  #debounceTimer = null  // Private field

  copy() {  // Public - called from data-action
    navigator.clipboard.writeText(this.sourceTarget.value)
    this.#showNotification()
  }

  #showNotification() {  // Private - internal only
    this.element.classList.add('success')
  }
}

Public methods: Those in data-action="controller#method" + lifecycle (connect, disconnect, *ValueChanged, *TargetConnected)

Private methods: Everything else — helpers, callbacks, utilities. Add #.

No business logic in Stimulus. Controllers coordinate UI only. Validations and data transforms go in Rails.

View Containers

Structure partials with prefixed dom_id for targeted updates:

<article id="<%= dom_id(card) %>" class="card">
  <div id="<%= dom_id(card, :status) %>">
    <%= render "cards/status", card: card %>
  </div>
  <div id="<%= dom_id(card, :header) %>">
    <%= render "cards/header", card: card %>
  </div>
</article>

Red Flags

Red flag	Fix
"card_#{@card.id}"	dom_id(@card)
turbo_stream.replace without method: :morph	Add method: :morph
Helper method without #	Add # prefix
One Stimulus controller doing 5+ things	Split into focused controllers
Validations in JavaScript	Move to Rails model
Animation logic in Stimulus	Use CSS transitions