Turbo 8 morphing & page refreshes

Turbo 8 added a second update model alongside targeted Turbo Streams: page refreshes with morphing. Render the current page again (e.g. submit → redirect back) and Turbo morphs only the changed DOM via idiomorph, preserving screen state. It's the simpler "happy path" — but it has sharp edges. This skill helps you pick the right tool and avoid the footguns.

Full background: references/morphing-guide.md. Real-world note: piazza-web/wip/analysis/08-turbo8-morphing-refreshes.md.

When to use

• Adding turbo_refreshes_with method: :morph, scroll: :preserve.
• Broadcasting live updates and considering broadcasts_refreshes vs targeted streams.
• Morphing resets UI state (a <details> reopens for everyone, a popover closes, scroll jumps, a JS-initialized widget breaks) after a refresh/broadcast.
• Reviewing a PR that enables morphing, especially in the global layout.

Decision guide

Need	Use
Submit-and-redirect-back with many small scattered changes	morph page refresh: turbo_refreshes_with method: :morph
Live multi-user updates, simplest server code, "good enough" fidelity	broadcasts_refreshes + turbo_stream_from @record
High-fidelity append/prepend (chat), surgical control	targeted streams (broadcast_append_to, etc.)
Reload one region during a full-page refresh / explicit .reload()	frame with refresh="morph"
Morph a single element instead of replacing it	turbo_stream.replace id, ..., method: :morph

Mantra (37signals): morphing is an implementation detail of a page refresh, not a new partial-update tool. Use targeted streams when you need precision.

broadcasts_refreshes (the simplification)

class Listing < ApplicationRecord
  broadcasts_refreshes      # after create/update/destroy → <turbo-stream action="refresh">
end

<%= turbo_stream_from @listing %>
<%= turbo_refreshes_with method: :morph, scroll: :preserve %>

Async via Turbo::Streams::BroadcastJob (needs a job backend), auto-debounced (only the last of a burst), and self-refreshes are deduped via X-Turbo-Request-Id.

Avoid the footguns (morphing resets browser-only state)

In order of preference:

1. data-turbo-permanent — exclude an element from morphing entirely.
2. turbo:before-morph-element / turbo:before-morph-attribute + a small Stimulus controller to veto a specific change (e.g. keep <details open> open).
3. Best — keep the state on the server (a user-pref record or a URL param like ?sidebar=1) so the re-render already matches the browser; morph is then a no-op.

Don't enable turbo_refreshes_with in the global layout without auditing stateful widgets first.

Check a repo

scripts/lint_morphing.sh path/to/rails-app

Reports: whether morph is enabled (and if it's global — in the layout — which is risky), stateful widgets (<details open>, <dialog>, scrollable/JS-controlled elements) that morphing may reset without a data-turbo-permanent / before-morph guard nearby, and _later broadcast usage that needs a job backend. Heuristic grep scan that names its ceiling — guidance, not a parser.