Utilities topic

Side effects, escape hatches and write grouping.

Effect runs a body under tracking and reruns it when what it read changes, coalescing a burst of writes into a single rerun and registering cleanups. listen and when build on it for callbacks that need the previous value or a future that completes on a condition, and Watch does the same for a tracked expression instead of a single signal — silent on creation, so it reacts to the transition rather than to the state that was already there.

untracked and peek read without subscribing. batch groups several writes so listeners see one notification with the final state, never the half-applied one in between.

Classes

Effect

A reactive side effect with automatic dependency tracking.

Watch<T>

A side effect on an auto-tracked expression, skipping the first run.

Extensions

ReadonlySignalSubscriptions on ReadonlySignal<T>

Side-effect subscriptions on any ReadonlySignal.

Functions

batch<T>(T run()) → T

Groups several writes into a single atomic update.

untracked<T>(T run()) → T

Runs run with dependency tracking suspended and returns its result.

Typedefs

EffectCleanup = void Function()

A cleanup callback registered by an Effect run.