one/dist/cjs/link/prefetchIntent.native.js

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

"use strict";

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 prefetchIntent_exports = {};
__export(prefetchIntent_exports, {
	createPrefetchIntent: () => createPrefetchIntent,
	observePrefetchIntent: () => observePrefetchIntent,
	startPrefetchIntent: () => startPrefetchIntent
});
module.exports = __toCommonJS(prefetchIntent_exports);
function createPrefetchIntent(options) {
	var { onPrefetch, maxReach = 500, perpWeight = 5, minSpeed = 8 } = options;
	var done = /* @__PURE__ */ new Set();
	var rects = [];
	var px = 0, py = 0, vx = 0, vy = 0;
	var moveCount = 0;
	var lastPrefetchMove = 0;
	function setRects(newRects) {
		rects = newRects.filter(function(r) {
			return !done.has(r.h);
		});
	}
	function move(x, y, dx, dy) {
		moveCount++;
		var smooth = moveCount < 3 ? .3 : .6;
		vx = vx * smooth + dx * (1 - smooth);
		vy = vy * smooth + dy * (1 - smooth);
		px = x;
		py = y;
		var speed = Math.sqrt(vx * vx + vy * vy);
		if (speed < minSpeed) return;
		var ux = vx / speed;
		var uy = vy / speed;
		var best = Infinity;
		var href = "";
		var _iteratorNormalCompletion = true, _didIteratorError = false, _iteratorError = void 0;
		try {
			for (var _iterator = rects[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
				var { r, h } = _step.value;
				var cx = (r.left + r.right) / 2 - px;
				var cy = (r.top + r.bottom) / 2 - py;
				var dist = Math.sqrt(cx * cx + cy * cy);
				var along = cx * ux + cy * uy;
				if (along < 0) continue;
				var perpX = cx - along * ux;
				var perpY = cy - along * uy;
				var perp = Math.sqrt(perpX * perpX + perpY * perpY);
				var baseRadius = Math.max(r.width, r.height) / 2 + 30;
				var distanceFactor = Math.max(.2, 1 - dist / 1e3);
				var radius = baseRadius * distanceFactor + 20;
				if (perp > radius) continue;
				var score = along + perp * perpWeight;
				if (score < best) {
					best = score;
					href = h;
				}
			}
		} catch (err) {
			_didIteratorError = true;
			_iteratorError = err;
		} finally {
			try {
				if (!_iteratorNormalCompletion && _iterator.return != null) {
					_iterator.return();
				}
			} finally {
				if (_didIteratorError) {
					throw _iteratorError;
				}
			}
		}
		if (href && best < maxReach && moveCount - lastPrefetchMove > 1) {
			done.add(href);
			rects = rects.filter(function(r2) {
				return r2.h !== href;
			});
			lastPrefetchMove = moveCount;
			onPrefetch(href);
		}
	}
	var nodes = /* @__PURE__ */ new Map();
	function observe(el, href) {
		nodes.set(el, href);
		return function() {
			nodes.delete(el);
			done.delete(href);
		};
	}
	return {
		setRects,
		move,
		observe,
		nodes,
		done
	};
}
var instance = null;
var started = false;
function startPrefetchIntent(onPrefetch) {
	if (started) return instance;
	started = true;
	instance = createPrefetchIntent({ onPrefetch });
	var frame = 0;
	var px = 0, py = 0;
	function measure() {
		if (!instance.nodes.size) return setTimeout(measure, 300);
		var io = new IntersectionObserver(function(entries) {
			io.disconnect();
			instance.setRects(entries.filter(function(e) {
				return e.isIntersecting;
			}).map(function(e) {
				return {
					r: e.boundingClientRect,
					h: instance.nodes.get(e.target)
				};
			}).filter(function(x) {
				return x.h;
			}));
			setTimeout(measure, 300);
		});
		instance.nodes.forEach(function(_, el) {
			return io.observe(el);
		});
	}
	measure();
	document.addEventListener("mousemove", function(e) {
		if (++frame % 4) return;
		var dx = e.clientX - px;
		var dy = e.clientY - py;
		px = e.clientX;
		py = e.clientY;
		instance.move(px, py, dx, dy);
	}, { passive: true });
	return instance;
}
function observePrefetchIntent(el, href) {
	if (!instance) return function() {};
	return instance.observe(el, href);
}

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