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frontend/node_modules/svelte/src/motion/tweened.js

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+/** @import { Task } from '../internal/client/types' */
+/** @import { Tweened } from './public' */
+/** @import { TweenedOptions } from './private' */
+import { writable } from '../store/shared/index.js';
+import { raf } from '../internal/client/timing.js';
+import { loop } from '../internal/client/loop.js';
+import { linear } from '../easing/index.js';
+import { is_date } from './utils.js';
+import { set, state } from '../internal/client/reactivity/sources.js';
+import { tag } from '../internal/client/dev/tracing.js';
+import { get, render_effect } from 'svelte/internal/client';
+import { DEV } from 'esm-env';
+
+/**
+ * @template T
+ * @param {T} a
+ * @param {T} b
+ * @returns {(t: number) => T}
+ */
+function get_interpolator(a, b) {
+	if (a === b || a !== a) return () => a;
+
+	const type = typeof a;
+	if (type !== typeof b || Array.isArray(a) !== Array.isArray(b)) {
+		throw new Error('Cannot interpolate values of different type');
+	}
+
+	if (Array.isArray(a)) {
+		const arr = /** @type {Array<any>} */ (b).map((bi, i) => {
+			return get_interpolator(/** @type {Array<any>} */ (a)[i], bi);
+		});
+
+		// @ts-ignore
+		return (t) => arr.map((fn) => fn(t));
+	}
+
+	if (type === 'object') {
+		if (!a || !b) {
+			throw new Error('Object cannot be null');
+		}
+
+		if (is_date(a) && is_date(b)) {
+			const an = a.getTime();
+			const bn = b.getTime();
+			const delta = bn - an;
+
+			// @ts-ignore
+			return (t) => new Date(an + t * delta);
+		}
+
+		const keys = Object.keys(b);
+
+		/** @type {Record<string, (t: number) => T>} */
+		const interpolators = {};
+		keys.forEach((key) => {
+			// @ts-ignore
+			interpolators[key] = get_interpolator(a[key], b[key]);
+		});
+
+		// @ts-ignore
+		return (t) => {
+			/** @type {Record<string, any>} */
+			const result = {};
+			keys.forEach((key) => {
+				result[key] = interpolators[key](t);
+			});
+			return result;
+		};
+	}
+
+	if (type === 'number') {
+		const delta = /** @type {number} */ (b) - /** @type {number} */ (a);
+		// @ts-ignore
+		return (t) => a + t * delta;
+	}
+
+	// for non-numeric values, snap to the final value immediately
+	return () => b;
+}
+
+/**
+ * A tweened store in Svelte is a special type of store that provides smooth transitions between state values over time.
+ *
+ * @deprecated Use [`Tween`](https://svelte.dev/docs/svelte/svelte-motion#Tween) instead
+ * @template T
+ * @param {T} [value]
+ * @param {TweenedOptions<T>} [defaults]
+ * @returns {Tweened<T>}
+ */
+export function tweened(value, defaults = {}) {
+	const store = writable(value);
+	/** @type {Task} */
+	let task;
+	let target_value = value;
+	/**
+	 * @param {T} new_value
+	 * @param {TweenedOptions<T>} [opts]
+	 */
+	function set(new_value, opts) {
+		target_value = new_value;
+
+		if (value == null) {
+			store.set((value = new_value));
+			return Promise.resolve();
+		}
+
+		/** @type {Task | null} */
+		let previous_task = task;
+
+		let started = false;
+		let {
+			delay = 0,
+			duration = 400,
+			easing = linear,
+			interpolate = get_interpolator
+		} = { ...defaults, ...opts };
+
+		if (duration === 0) {
+			if (previous_task) {
+				previous_task.abort();
+				previous_task = null;
+			}
+			store.set((value = target_value));
+			return Promise.resolve();
+		}
+
+		const start = raf.now() + delay;
+
+		/** @type {(t: number) => T} */
+		let fn;
+		task = loop((now) => {
+			if (now < start) return true;
+			if (!started) {
+				fn = interpolate(/** @type {any} */ (value), new_value);
+				if (typeof duration === 'function')
+					duration = duration(/** @type {any} */ (value), new_value);
+				started = true;
+			}
+			if (previous_task) {
+				previous_task.abort();
+				previous_task = null;
+			}
+			const elapsed = now - start;
+			if (elapsed > /** @type {number} */ (duration)) {
+				store.set((value = new_value));
+				return false;
+			}
+			// @ts-ignore
+			store.set((value = fn(easing(elapsed / duration))));
+			return true;
+		});
+		return task.promise;
+	}
+	return {
+		set,
+		update: (fn, opts) =>
+			set(fn(/** @type {any} */ (target_value), /** @type {any} */ (value)), opts),
+		subscribe: store.subscribe
+	};
+}
+
+/**
+ * A wrapper for a value that tweens smoothly to its target value. Changes to `tween.target` will cause `tween.current` to
+ * move towards it over time, taking account of the `delay`, `duration` and `easing` options.
+ *
+ * ```svelte
+ * <script>
+ * 	import { Tween } from 'svelte/motion';
+ *
+ * 	const tween = new Tween(0);
+ * </script>
+ *
+ * <input type="range" bind:value={tween.target} />
+ * <input type="range" bind:value={tween.current} disabled />
+ * ```
+ * @template T
+ * @since 5.8.0
+ */
+export class Tween {
+	#current;
+	#target;
+
+	/** @type {TweenedOptions<T>} */
+	#defaults;
+
+	/** @type {import('../internal/client/types').Task | null} */
+	#task = null;
+
+	/**
+	 * @param {T} value
+	 * @param {TweenedOptions<T>} options
+	 */
+	constructor(value, options = {}) {
+		this.#current = state(value);
+		this.#target = state(value);
+		this.#defaults = options;
+
+		if (DEV) {
+			tag(this.#current, 'Tween.current');
+			tag(this.#target, 'Tween.target');
+		}
+	}
+
+	/**
+	 * Create a tween whose value is bound to the return value of `fn`. This must be called
+	 * inside an effect root (for example, during component initialisation).
+	 *
+	 * ```svelte
+	 * <script>
+	 * 	import { Tween } from 'svelte/motion';
+	 *
+	 * 	let { number } = $props();
+	 *
+	 * 	const tween = Tween.of(() => number);
+	 * </script>
+	 * ```
+	 * @template U
+	 * @param {() => U} fn
+	 * @param {TweenedOptions<U>} [options]
+	 */
+	static of(fn, options) {
+		const tween = new Tween(fn(), options);
+
+		render_effect(() => {
+			tween.set(fn());
+		});
+
+		return tween;
+	}
+
+	/**
+	 * Sets `tween.target` to `value` and returns a `Promise` that resolves if and when `tween.current` catches up to it.
+	 *
+	 * If `options` are provided, they will override the tween's defaults.
+	 * @param {T} value
+	 * @param {TweenedOptions<T>} [options]
+	 * @returns
+	 */
+	set(value, options) {
+		set(this.#target, value);
+
+		let {
+			delay = 0,
+			duration = 400,
+			easing = linear,
+			interpolate = get_interpolator
+		} = { ...this.#defaults, ...options };
+
+		if (duration === 0) {
+			this.#task?.abort();
+			set(this.#current, value);
+			return Promise.resolve();
+		}
+
+		const start = raf.now() + delay;
+
+		/** @type {(t: number) => T} */
+		let fn;
+		let started = false;
+		let previous_task = this.#task;
+
+		this.#task = loop((now) => {
+			if (now < start) {
+				return true;
+			}
+
+			if (!started) {
+				started = true;
+
+				const prev = this.#current.v;
+
+				fn = interpolate(prev, value);
+
+				if (typeof duration === 'function') {
+					duration = duration(prev, value);
+				}
+
+				previous_task?.abort();
+			}
+
+			const elapsed = now - start;
+
+			if (elapsed > /** @type {number} */ (duration)) {
+				set(this.#current, value);
+				return false;
+			}
+
+			set(this.#current, fn(easing(elapsed / /** @type {number} */ (duration))));
+			return true;
+		});
+
+		return this.#task.promise;
+	}
+
+	get current() {
+		return get(this.#current);
+	}
+
+	get target() {
+		return get(this.#target);
+	}
+
+	set target(v) {
+		this.set(v);
+	}
+}