seitu/dist/core/debounced/index.mjs

import { createReadableSubscription, createSubscription } from "../subscription/index.mjs";
//#region src/core/debounced/index.ts
/**
* Debounces updates from a source. Unsubscribed `get()` reads through;
* subscribed `get()` returns the last emitted value.
*
* @example
* ```ts twoslash
* import { createStore, createDebounced } from 'seitu'
*
* const store = createStore('')
* const debounced = createDebounced(store, 300)
* debounced.subscribe(value => console.log('debounced:', value))
* debounced.flush()
* ```
*/
function createDebounced(source, wait) {
	let state = source.get();
	let timeoutId;
	let active = false;
	const cancel = () => {
		clearTimeout(timeoutId);
		timeoutId = void 0;
	};
	const { subscribe, notify } = createSubscription({ onFirstSubscribe() {
		state = source.get();
		active = true;
		const unsubscribe = source.subscribe(() => {
			clearTimeout(timeoutId);
			timeoutId = setTimeout(() => {
				timeoutId = void 0;
				state = source.get();
				notify();
			}, wait);
		});
		return () => {
			cancel();
			active = false;
			unsubscribe();
		};
	} });
	const flush = () => {
		if (timeoutId === void 0) return;
		cancel();
		state = source.get();
		notify();
	};
	const get = () => active ? state : source.get();
	return {
		...createReadableSubscription(get, subscribe, notify, source.getServer),
		cancel,
		flush
	};
}
//#endregion
export { createDebounced };