Support Svelte 3

fixes #546, #551, #552, #554

runtime/src/app/start/index.ts

@@ -0,0 +1,130 @@
+import {
+	cid,
+	history,
+	initial_data,
+	navigate,
+	scroll_history,
+	scroll_state,
+	select_target,
+	set_target,
+	uid,
+	set_uid,
+	set_cid
+} from '../app';
+import prefetch from '../prefetch/index';
+
+export default function start(opts: {
+	target: Node
+}) {
+	if ('scrollRestoration' in history) {
+		history.scrollRestoration = 'manual';
+	}
+
+	set_target(opts.target);
+
+	addEventListener('click', handle_click);
+	addEventListener('popstate', handle_popstate);
+
+	// prefetch
+	addEventListener('touchstart', trigger_prefetch);
+	addEventListener('mousemove', handle_mousemove);
+
+	return Promise.resolve().then(() => {
+		const { hash, href } = location;
+
+		history.replaceState({ id: uid }, '', href);
+
+		if (!initial_data.error) {
+			const target = select_target(new URL(location.href));
+			if (target) return navigate(target, uid, false, hash);
+		}
+	});
+}
+
+let mousemove_timeout: NodeJS.Timer;
+
+function handle_mousemove(event: MouseEvent) {
+	clearTimeout(mousemove_timeout);
+	mousemove_timeout = setTimeout(() => {
+		trigger_prefetch(event);
+	}, 20);
+}
+
+function trigger_prefetch(event: MouseEvent | TouchEvent) {
+	const a: HTMLAnchorElement = <HTMLAnchorElement>find_anchor(<Node>event.target);
+	if (!a || a.rel !== 'prefetch') return;
+
+	prefetch(a.href);
+}
+
+function handle_click(event: MouseEvent) {
+	// Adapted from https://github.com/visionmedia/page.js
+	// MIT license https://github.com/visionmedia/page.js#license
+	if (which(event) !== 1) return;
+	if (event.metaKey || event.ctrlKey || event.shiftKey) return;
+	if (event.defaultPrevented) return;
+
+	const a: HTMLAnchorElement | SVGAElement = <HTMLAnchorElement | SVGAElement>find_anchor(<Node>event.target);
+	if (!a) return;
+
+	if (!a.href) return;
+
+	// check if link is inside an svg
+	// in this case, both href and target are always inside an object
+	const svg = typeof a.href === 'object' && a.href.constructor.name === 'SVGAnimatedString';
+	const href = String(svg ? (<SVGAElement>a).href.baseVal : a.href);
+
+	if (href === location.href) {
+		if (!location.hash) event.preventDefault();
+		return;
+	}
+
+	// Ignore if tag has
+	// 1. 'download' attribute
+	// 2. rel='external' attribute
+	if (a.hasAttribute('download') || a.getAttribute('rel') === 'external') return;
+
+	// Ignore if <a> has a target
+	if (svg ? (<SVGAElement>a).target.baseVal : a.target) return;
+
+	const url = new URL(href);
+
+	// Don't handle hash changes
+	if (url.pathname === location.pathname && url.search === location.search) return;
+
+	const target = select_target(url);
+	if (target) {
+		const noscroll = a.hasAttribute('sapper-noscroll');
+		navigate(target, null, noscroll, url.hash);
+		event.preventDefault();
+		history.pushState({ id: cid }, '', url.href);
+	}
+}
+
+function which(event: MouseEvent) {
+	return event.which === null ? event.button : event.which;
+}
+
+function find_anchor(node: Node) {
+	while (node && node.nodeName.toUpperCase() !== 'A') node = node.parentNode; // SVG <a> elements have a lowercase name
+	return node;
+}
+
+function handle_popstate(event: PopStateEvent) {
+	scroll_history[cid] = scroll_state();
+
+	if (event.state) {
+		const url = new URL(location.href);
+		const target = select_target(url);
+		if (target) {
+			navigate(target, event.state.id);
+		} else {
+			location.href = location.href;
+		}
+	} else {
+		// hashchange
+		set_uid(uid + 1);
+		set_cid(uid);
+		history.replaceState({ id: cid }, '', location.href);
+	}
+}