@motion-core/motion-gpu/dist/core/current-value.js

Framework-agnostic WebGPU runtime for fullscreen WGSL shaders with explicit Svelte, React, and Vue adapter entrypoints.

//#region src/lib/core/current-value.ts
var NO_PENDING_ERROR = Symbol("motiongpu-current-no-error");
/**
* Creates a writable value with immediate subscription semantics.
* Accepted writes are delivered FIFO to a subscriber snapshot. `onChange` runs
* after that snapshot for each value, preserving the original callback order.
*/
function createCurrentWritable(initialValue, onChange) {
	let current = initialValue;
	let currentVersion = 0;
	const subscribers = /* @__PURE__ */ new Set();
	const deliveredVersions = /* @__PURE__ */ new Map();
	const pendingValues = [];
	let pendingIndex = 0;
	let isFlushing = false;
	const flush = () => {
		if (isFlushing) return;
		isFlushing = true;
		let firstError = NO_PENDING_ERROR;
		try {
			while (pendingIndex < pendingValues.length) {
				const { value, version } = pendingValues[pendingIndex];
				pendingIndex += 1;
				const snapshot = Array.from(subscribers);
				for (const run of snapshot) {
					if (!subscribers.has(run) || (deliveredVersions.get(run) ?? -1) >= version) continue;
					deliveredVersions.set(run, version);
					try {
						run(value);
					} catch (error) {
						if (firstError === NO_PENDING_ERROR) firstError = error;
					}
				}
				try {
					onChange?.(value);
				} catch (error) {
					if (firstError === NO_PENDING_ERROR) firstError = error;
				}
			}
		} finally {
			pendingValues.length = 0;
			pendingIndex = 0;
			isFlushing = false;
		}
		if (firstError !== NO_PENDING_ERROR) throw firstError;
	};
	const set = (value) => {
		if (Object.is(current, value)) return;
		current = value;
		currentVersion += 1;
		pendingValues.push({
			value,
			version: currentVersion
		});
		flush();
	};
	return {
		get current() {
			return current;
		},
		subscribe(run) {
			subscribers.add(run);
			deliveredVersions.set(run, currentVersion);
			try {
				run(current);
			} catch (error) {
				subscribers.delete(run);
				deliveredVersions.delete(run);
				throw error;
			}
			return () => {
				subscribers.delete(run);
				deliveredVersions.delete(run);
			};
		},
		set,
		update(updater) {
			set(updater(current));
		}
	};
}
//#endregion
export { createCurrentWritable };

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