All files / src/store/shared index.js

100% Statements 218/218
100% Branches 38/38
100% Functions 10/10
100% Lines 215/215

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 2162x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 38x 38x 38x 38x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 655x 655x 655x 655x 655x 655x 655x 655x 655x 655x 655x 535x 523x 523x 368x 368x 368x 435x 435x 435x 368x 334x 435x 435x 334x 334x 368x 523x 535x 655x 655x 655x 655x 655x 655x 72x 72x 655x 655x 655x 655x 655x 655x 655x 721x 721x 721x 721x 640x 640x 721x 721x 727x 727x 632x 632x 632x 721x 721x 655x 655x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 34x 34x 34x 34x 2x 2x 32x 32x 33x 33x 33x 33x 33x 33x 75x 2x 2x 73x 75x 75x 49x 75x 24x 24x 33x 33x 39x 39x 39x 82x 82x 82x 42x 42x 39x 39x 43x 43x 39x 33x 33x 33x 33x 32x 32x 32x 32x 32x 32x 33x 32x 32x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 1x 1x 1x 1x 1x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 59x 59x 59x 59x 59x  
/** @import { Readable, StartStopNotifier, Subscriber, Unsubscriber, Updater, Writable } from '../public.js' */
/** @import { Stores, StoresValues, SubscribeInvalidateTuple } from '../private.js' */
import { noop, run_all } from '../../internal/shared/utils.js';
import { safe_not_equal } from '../../internal/client/reactivity/equality.js';
import { subscribe_to_store } from '../utils.js';
 
/**
 * @type {Array<SubscribeInvalidateTuple<any> | any>}
 */
const subscriber_queue = [];
 
/**
 * Creates a `Readable` store that allows reading by subscription.
 *
 * https://svelte.dev/docs/svelte-store#readable
 * @template T
 * @param {T} [value] initial value
 * @param {StartStopNotifier<T>} [start]
 * @returns {Readable<T>}
 */
export function readable(value, start) {
	return {
		subscribe: writable(value, start).subscribe
	};
}
 
/**
 * Create a `Writable` store that allows both updating and reading by subscription.
 *
 * https://svelte.dev/docs/svelte-store#writable
 * @template T
 * @param {T} [value] initial value
 * @param {StartStopNotifier<T>} [start]
 * @returns {Writable<T>}
 */
export function writable(value, start = noop) {
	/** @type {Unsubscriber | null} */
	let stop = null;
 
	/** @type {Set<SubscribeInvalidateTuple<T>>} */
	const subscribers = new Set();
 
	/**
	 * @param {T} new_value
	 * @returns {void}
	 */
	function set(new_value) {
		if (safe_not_equal(value, new_value)) {
			value = new_value;
			if (stop) {
				// store is ready
				const run_queue = !subscriber_queue.length;
				for (const subscriber of subscribers) {
					subscriber[1]();
					subscriber_queue.push(subscriber, value);
				}
				if (run_queue) {
					for (let i = 0; i < subscriber_queue.length; i += 2) {
						subscriber_queue[i][0](subscriber_queue[i + 1]);
					}
					subscriber_queue.length = 0;
				}
			}
		}
	}
 
	/**
	 * @param {Updater<T>} fn
	 * @returns {void}
	 */
	function update(fn) {
		set(fn(/** @type {T} */ (value)));
	}
 
	/**
	 * @param {Subscriber<T>} run
	 * @param {() => void} [invalidate]
	 * @returns {Unsubscriber}
	 */
	function subscribe(run, invalidate = noop) {
		/** @type {SubscribeInvalidateTuple<T>} */
		const subscriber = [run, invalidate];
		subscribers.add(subscriber);
		if (subscribers.size === 1) {
			stop = start(set, update) || noop;
		}
		run(/** @type {T} */ (value));
		return () => {
			subscribers.delete(subscriber);
			if (subscribers.size === 0 && stop) {
				stop();
				stop = null;
			}
		};
	}
	return { set, update, subscribe };
}
 
/**
 * Derived value store by synchronizing one or more readable stores and
 * applying an aggregation function over its input values.
 *
 * https://svelte.dev/docs/svelte-store#derived
 * @template {Stores} S
 * @template T
 * @overload
 * @param {S} stores
 * @param {(values: StoresValues<S>, set: (value: T) => void, update: (fn: Updater<T>) => void) => Unsubscriber | void} fn
 * @param {T} [initial_value]
 * @returns {Readable<T>}
 */
/**
 * Derived value store by synchronizing one or more readable stores and
 * applying an aggregation function over its input values.
 *
 * https://svelte.dev/docs/svelte-store#derived
 * @template {Stores} S
 * @template T
 * @overload
 * @param {S} stores
 * @param {(values: StoresValues<S>) => T} fn
 * @param {T} [initial_value]
 * @returns {Readable<T>}
 */
/**
 * @template {Stores} S
 * @template T
 * @param {S} stores
 * @param {Function} fn
 * @param {T} [initial_value]
 * @returns {Readable<T>}
 */
export function derived(stores, fn, initial_value) {
	const single = !Array.isArray(stores);
	/** @type {Array<Readable<any>>} */
	const stores_array = single ? [stores] : stores;
	if (!stores_array.every(Boolean)) {
		throw new Error('derived() expects stores as input, got a falsy value');
	}
	const auto = fn.length < 2;
	return readable(initial_value, (set, update) => {
		let started = false;
		/** @type {T[]} */
		const values = [];
		let pending = 0;
		let cleanup = noop;
		const sync = () => {
			if (pending) {
				return;
			}
			cleanup();
			const result = fn(single ? values[0] : values, set, update);
			if (auto) {
				set(result);
			} else {
				cleanup = typeof result === 'function' ? result : noop;
			}
		};
		const unsubscribers = stores_array.map((store, i) =>
			subscribe_to_store(
				store,
				(value) => {
					values[i] = value;
					pending &= ~(1 << i);
					if (started) {
						sync();
					}
				},
				() => {
					pending |= 1 << i;
				}
			)
		);
		started = true;
		sync();
		return function stop() {
			run_all(unsubscribers);
			cleanup();
			// We need to set this to false because callbacks can still happen despite having unsubscribed:
			// Callbacks might already be placed in the queue which doesn't know it should no longer
			// invoke this derived store.
			started = false;
		};
	});
}
 
/**
 * Takes a store and returns a new one derived from the old one that is readable.
 *
 * https://svelte.dev/docs/svelte-store#readonly
 * @template T
 * @param {Readable<T>} store  - store to make readonly
 * @returns {Readable<T>}
 */
export function readonly(store) {
	return {
		// @ts-expect-error TODO i suspect the bind is unnecessary
		subscribe: store.subscribe.bind(store)
	};
}
 
/**
 * Get the current value from a store by subscribing and immediately unsubscribing.
 *
 * https://svelte.dev/docs/svelte-store#get
 * @template T
 * @param {Readable<T>} store
 * @returns {T}
 */
export function get(store) {
	let value;
	subscribe_to_store(store, (_) => (value = _))();
	// @ts-expect-error
	return value;
}