adopt

function · packages/richtext-dom/src/index.ts:232

function adopt(
  existing: Element,
  content: RichText.Document,
  rendering?: RichText.Rendering,
  decorations?: RichText.DecorationSet,
): EditorDom | undefined

Takes over a subtree already in the page when it is exactly what mount would build, such as server markup the browser parsed (§145): the elements stay, and the identity index is built around them. Undefined when anything differs, so the caller builds afresh.

Markup cannot carry an empty text node, and a caret in an empty run needs one, so an empty run's content is replaced by what mount gives it; the run's element stays.