useLatest

Keep the newest value in a stable reference without rebuilding.

What it does

useLatest returns one stable ObjectRef<T> whose value is refreshed during every build. Updating the cell does not schedule another build, so it is useful when a long-lived callback must read current props or state without being recreated.

Signature and parameters

ObjectRef<T> useLatest<T>(T value)

value is copied into the reference on every build. The return type is the hook-owned ObjectRef<T>; its identity remains stable at the same hook position.

Usage

final latestQuery = useLatest(query);

useTimeout(() {
  analytics.recordSearch(latestQuery.value);
}, const Duration(seconds: 1));

Live demo

Interactive useLatest demo

Stable reference contains 0

Ownership and lifecycle

The hook owns only the reference, not the supplied value. The cell is updated synchronously during build and discarded with the hook state. Mutating latest.value manually is allowed but will be overwritten by the next build.

Server rendering

useLatest works during server and client builds. Use deterministic values when the reference influences rendered output; the server reference is independent from the client reference.

Common mistakes

Do not use it for values that should redraw the UI because changing the reference does not rebuild. Prefer useState for render state. Do not capture latest.value before an asynchronous boundary; read it when the callback actually runs.

Use useRef when the application, rather than the hook, should mutate the cell. useCallback, useTimeout, useInterval, and subscription hooks commonly pair with useLatest.