one/dist/cjs/link/prefetchViewport.cjs

One is a React framework for web, iOS, and Android apps.

var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __getOwnPropNames = Object.getOwnPropertyNames;
var __hasOwnProp = Object.prototype.hasOwnProperty;
var __export = (target, all) => {
	for (var name in all) __defProp(target, name, {
		get: all[name],
		enumerable: true
	});
};
var __copyProps = (to, from, except, desc) => {
	if (from && typeof from === "object" || typeof from === "function") {
		for (let key of __getOwnPropNames(from)) if (!__hasOwnProp.call(to, key) && key !== except) __defProp(to, key, {
			get: () => from[key],
			enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable
		});
	}
	return to;
};
var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);
var prefetchViewport_exports = {};
__export(prefetchViewport_exports, {
	createPrefetchViewport: () => createPrefetchViewport,
	observePrefetchViewport: () => observePrefetchViewport,
	startPrefetchViewport: () => startPrefetchViewport
});
module.exports = __toCommonJS(prefetchViewport_exports);
function createPrefetchViewport() {
	const done = /* @__PURE__ */ new Set();
	const nodes = /* @__PURE__ */ new Map();
	let io = null;
	let onPrefetch = null;
	function getObserver() {
		if (io) return io;
		io = new IntersectionObserver((entries) => {
			for (const entry of entries) {
				if (!entry.isIntersecting) continue;
				const href = nodes.get(entry.target);
				if (href && !done.has(href)) {
					done.add(href);
					onPrefetch?.(href);
				}
			}
		}, { threshold: .5 });
		return io;
	}
	function start(prefetch) {
		onPrefetch = prefetch;
	}
	function observe(el, href) {
		nodes.set(el, href);
		getObserver().observe(el);
		return () => {
			nodes.delete(el);
			io?.unobserve(el);
			done.delete(href);
		};
	}
	return {
		start,
		observe,
		done,
		nodes
	};
}
let instance = null;
function startPrefetchViewport(prefetch) {
	if (!instance) instance = createPrefetchViewport();
	instance.start(prefetch);
}
function observePrefetchViewport(el, href) {
	if (!instance) instance = createPrefetchViewport();
	return instance.observe(el, href);
}