FragmentSwapPolicy

FragmentSwapPolicy = "always" | "before-paint" | "never"

Defined in: fragments.ts:65

Whether a response that arrives AFTER a field’s fallback has landed may replace it. It may not: text a visitor can see is never replaced.

"never" — the behaviour of every field. A field holds (reserved, invisible) while the response is in flight; a response inside the hold lands in the reserved space, and once the fallback has landed it is final for the view.

"before-paint" and "always" — deprecated. Still accepted, so existing call sites keep compiling, and they now behave exactly like "never": no late response replaces a landed fallback. Presentation only: the policy never reaches the wire and never enters the schema hash.