katanakit-js / useCreateStorageSignal

Function: useCreateStorageSignal()

function useCreateStorageSignal<T>(
   key, 
   fallbackValue, 
   target?
): [SignalGetter<T>, SignalSetter<T>];

Defined in: src/infrastructure/storage/storage-signal.service.ts:32

Creates a signal that persists its value to a storage backend (localStorage, sessionStorage, etc.). Reads the initial value from storage on creation.

This lives in the infrastructure layer, not in core, because it is the one reactive helper that performs real I/O. Core stays free of runtime I/O; the pure signal primitives (useCreateSignal, useCreateEffect, useCreateMemo, …) remain in core/services/reactive.service.ts.

Type Parameters

Type Parameter	Description
T	The signal value type.

Parameters

Parameter	Type	Default value	Description
key	string	undefined	Storage key.
fallbackValue	T	undefined	Value used when the key is not in storage.
target	"localStorage" | "sessionStorage"	"localStorage"	Storage backend (defaults to "localStorage").

Returns

[SignalGetter<T>, SignalSetter<T>]

A tuple of [getter, setter]. The setter writes through to storage.

Example

import { useCreateStorageSignal } from "katanakit-js";

const [theme, setTheme] = useCreateStorageSignal("theme", "dark");
theme(); // "dark" (or whatever was stored)
setTheme("light"); // persists to localStorage