signal()

Create a reactive value that triggers updates when changed.

Signature

function signal<T>(initialValue: T): Signal<T>

Parameters

Param	Type	Description
initialValue	T	The initial value

Returns

Signal<T> with:

Property	Type	Description
.value	T	Read or write (triggers reactivity)
.peek()	T	Read without tracking
.set(value)	void	Set a new value
.update(fn)	void	Update via function
.subscribe(fn)	() => void	Subscribe to changes, returns unsubscribe

Examples

import { signal } from "@whisq/core";

const count = signal(0);
count.value;              // 0 (read — triggers tracking)
count.value = 5;          // (write — triggers updates)
count.update(n => n + 1); // 6
count.peek();             // 6 (read — no tracking)

🐱 Whisker Tip

Use peek() inside effects when you need a value without creating a dependency. This prevents infinite loops.

Related primitives

• computed() — derived values (read-only signals that recompute when their inputs change).
• effect() — run side effects when tracked signals change.
• batch() — group multiple writes into one notification.
• persistedSignal() — a Signal<T> backed by localStorage / sessionStorage (sub-path import).
• signalMap(), signalSet() — reactive collections with per-key / per-value subscriptions.
• partition() — split a signal-held array into matching / not-matching derived signals.