Morph mutations

streamMutations covers Turbo Stream morphs (<turbo-stream method="morph">). The other two morph paths, both from Turbo 8, are:

• the Drive page refresh: <meta name="turbo-refresh-method" content="morph">,
• the frame refresh: <turbo-frame refresh="morph">.

They fire turbo:before-render / turbo:before-frame-render with renderMethod: "morph" and morph the container in place. By default the handler treats them like a replace: it unmounts then re-mounts the whole container, re-initializing listeners even on the nodes the morph preserved.

Per-element refresh

Set morphMutations: true to instead skip that coarse re-init on morph renders and refresh only the nodes Turbo actually morphed, via the turbo:morph-element event, leaving preserved widgets (an open select, a focused field) untouched:

new TurboHandler({
    onMount: (container) => app.mount(container),
    onUnmount: (container) => app.unmount(container),
    morphMutations: true,
})

With the option on:

Render	Behavior
Drive morph	No onUnmount / onMount of the container, before or after the render.
Frame morph	No onUnmount / onMount of the frame, before the render or on turbo:frame-load.
Each element morphed	onUnmount(element) then onMount(element); an exception is logged and does not stop the others.
Replace (non-morph) render	Unchanged: the whole container or frame is unmounted, then mounted.

Scope

• It covers elements morphed in place. Subtrees a morph adds or removes wholesale aren’t re-mounted by this path.
• It requires onMount / onUnmount to be safe to call on an individual element.
• Without the option, turbo:morph-element is ignored.