SvelteReference

svelte/store

import {
	function derived<S extends Stores, T>(stores: S, fn: (values: StoresValues<S>, set: (value: T) => void, update: (fn: Updater<T>) => void) => Unsubscriber | void, initial_value?: T | undefined): Readable<T> (+1 overload)Derived value store by synchronizing one or more readable stores and
applying an aggregation function over its input values.
derived,
	function fromStore<V>(store: Writable<V>): {
    current: V;
} (+1 overload)fromStore,
	function get<T>(store: Readable<T>): TGet the current value from a store by subscribing and immediately unsubscribing.
get,
	function readable<T>(value?: T | undefined, start?: StartStopNotifier<T> | undefined): Readable<T>Creates a Readable store that allows reading by subscription.
@paramvalue initial valuereadable,
	function readonly<T>(store: Readable<T>): Readable<T>Takes a store and returns a new one derived from the old one that is readable.
@paramstore - store to make readonlyreadonly,
	function toStore<V>(get: () => V, set: (v: V) => void): Writable<V> (+1 overload)toStore,
	function writable<T>(value?: T | undefined, start?: StartStopNotifier<T> | undefined): Writable<T>Create a Writable store that allows both updating and reading by subscription.
@paramvalue initial valuewritable
} from 'svelte/store';

derived

Derived value store by synchronizing one or more readable stores and applying an aggregation function over its input values.

function derived<S extends Stores, T>(
	stores: S,
	fn: (
		values: StoresValues<S>,
		set: (value: T) => void,
		update: (fn: Updater<T>) => void
	) => Unsubscriber | void,
	initial_value?: T | undefined
): Readable<T>;

function derived<S extends Stores, T>(
	stores: S,
	fn: (values: StoresValues<S>) => T,
	initial_value?: T | undefined
): Readable<T>;

fromStore

function fromStore<V>(store: Writable<V>): {
	current: V;
};

function fromStore<V>(store: Readable<V>): {
	readonly current: V;
};

get

Get the current value from a store by subscribing and immediately unsubscribing.

function get<T>(store: Readable<T>): T;

readable

Creates a Readable store that allows reading by subscription.

function readable<T>(
	value?: T | undefined,
	start?: StartStopNotifier<T> | undefined
): Readable<T>;

readonly

Takes a store and returns a new one derived from the old one that is readable.

function readonly<T>(store: Readable<T>): Readable<T>;

toStore

function toStore<V>(
	get: () => V,
	set: (v: V) => void
): Writable<V>;

function toStore<V>(get: () => V): Readable<V>;

writable

Create a Writable store that allows both updating and reading by subscription.

function writable<T>(
	value?: T | undefined,
	start?: StartStopNotifier<T> | undefined
): Writable<T>;

Readable

Readable interface for subscribing.

interface Readable<T> {…}

subscribe(this: void, run: Subscriber<T>, invalidate?: () => void): Unsubscriber;

run subscription callback
invalidate cleanup callback

Subscribe on value changes.

StartStopNotifier

Start and stop notification callbacks. This function is called when the first subscriber subscribes.

type StartStopNotifier<T> = (
	set: (value: T) => void,
	update: (fn: Updater<T>) => void
) => void | (() => void);

Subscriber

Callback to inform of a value updates.

type Subscriber<T> = (value: T) => void;

Unsubscriber

Unsubscribes from value updates.

type Unsubscriber = () => void;

Updater

Callback to update a value.

type Updater<T> = (value: T) => T;

Writable

Writable interface for both updating and subscribing.

interface Writable<T> extends Readable<T> {…}

set(this: void, value: T): void;

value to set

Set value and inform subscribers.

update(this: void, updater: Updater<T>): void;

updater callback

Update value using callback and inform subscribers.

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