Interface: SignalWatcher

API / @xmachines/play-signals / SignalWatcher

Defined in: packages/play-signals/src/types.ts:169

The watcher. It observes each signal change and schedules an effect

Signal.subtle.Watcher observes more than one signal, and it groups the updates. It is the low-level primitive, and a framework uses it to make a reactive effect.

Example

import { Signal } from "@xmachines/play-signals";

const count = new Signal.State(0);
const doubled = new Signal.Computed(() => count.get() * 2);

const watcher = new Signal.subtle.Watcher(() => {
  queueMicrotask(() => {
    const pending = watcher.getPending();
    console.log("Signals changed:", pending.length);
  });
});

watcher.watch(count);
watcher.watch(doubled);

count.set(5); // The watcher schedules the notification in a microtask

Methods

getPending()

getPending(): (
  | SignalState<unknown>
  | SignalComputed<unknown>)[];

Defined in: packages/play-signals/src/types.ts:189

Returns the signals that changed after the last check

Returns

( | SignalState<unknown> | SignalComputed<unknown>)[]

The array of the signals with an update that waits

---

unwatch()

unwatch(signal): void;

Defined in: packages/play-signals/src/types.ts:182

Stops the watch of one signal

Parameters

Parameter	Type	Description
signal	| SignalState<unknown> | SignalComputed<unknown>	The signal to leave

Returns

void

---

watch()

watch(signal): void;

Defined in: packages/play-signals/src/types.ts:175

Starts the watch of one signal

Parameters

Parameter	Type	Description
signal	| SignalState<unknown> | SignalComputed<unknown>	The signal to observe: a State or a Computed

Returns

void