@spec format_patch(iodata() | tuple() | nil, keyword()) :: String.t()

Formats an element patch event without writing to a connection.

@spec format_remove(String.t(), keyword()) :: String.t()

Formats an element removal event without writing to a connection.

@spec patch(Plug.Conn.t(), iodata() | tuple() | nil, keyword()) :: Plug.Conn.t()

Sends HTML elements to the browser for DOM patching.

Skipping unchanged patches

Inside StarView.Stream.run/2, only_changed: true with an explicit :key skips a patch whose HTML, selector, mode, namespace and view-transition setting and SSE metadata all equal the last patch sent under that key on this stream.

patch(conn, html, key: :orders, selector: "#orders", only_changed: true)

Only idempotent modes (:outer, :inner, :replace) are accepted, since repeating an append, prepend, before, after or remove has a visible effect. The comparison uses a SHA-256 digest. Each stream tracks up to 64 keys; later keys always send. A new stream starts empty, and conns outside an active run/2 (such as event responses) always send. format_patch/2 ignores these options.

The stream only knows what it sent, not the browser's final DOM. Any other element patch or removal on the same stream (including execute_script/3) clears every remembered key, so the next keyed patch sends again. Event responses, other streams, raw StarView.send/4 events and browser code can still change the DOM unseen: use only_changed only for a region this stream owns exclusively. Give each key its own non-overlapping region; two keys that target the same or nested elements can skip a patch the page needs.

@spec remove(Plug.Conn.t(), String.t(), keyword()) :: Plug.Conn.t()

Sends an element removal patch.