What is rebuilt when
Fallbacks: Show and Switch read fallback lazily when it is first needed; For and Index show it while the list is empty and dispose it when rows appear;…
| Component | Rebuilds its children when | Keeps them when |
|---|---|---|
Show |
the truthiness of when flips; with keyed, the identity of when changes |
when changes to another truthy value |
Switch |
a different Match becomes the first truthy one; a keyed Match changes identity |
the same Match stays selected |
For (unkeyed) |
an item reference is new (a row is created) or gone (its row is disposed) | the same reference stays in the list, wherever it moves |
For (keyed) |
a key is new or gone | the key stays; a new object under it only updates item() |
Index |
the length grows or shrinks | the position exists; the value at it changes item() |
Dynamic |
component changes |
other props change (they update in place) |
Portal |
never; moving mount moves the nodes |
children's own bindings update in place |
Fallbacks: Show and Switch read fallback lazily when it is first needed; For and Index show it while the list is empty and dispose it when rows appear; Suspense and ErrorBoundary are described in Suspense and resources and Error handling.