const detach = node => {
node.parentNode.removeChild(node);
};
let component;
let target;
let routes;
const scroll_history = {};
let uid = 1;
let cid;
if ('scrollRestoration' in history) {
history.scrollRestoration = 'manual'
}
function select_route(url) {
if (url.origin !== window.location.origin) return null;
for (const route of routes) {
const match = route.pattern.exec(url.pathname);
if (match) {
const params = route.params(match);
const query = {};
for (const [key, value] of url.searchParams) query[key] = value || true;
return { route, data: { params, query } };
}
}
}
function render(Component, data, scroll) {
Promise.resolve(
Component.preload ? Component.preload(data) : {}
).then(preloaded => {
if (component) {
component.destroy();
} else {
// first load — remove SSR'd contents
const start = document.querySelector('#sapper-head-start');
let end = document.querySelector('#sapper-head-end');
if (start && end) {
while (start.nextSibling !== end) detach(start.nextSibling);
detach(start);
detach(end);
}
// preload additional routes
routes.reduce((promise, route) => promise.then(route.load), Promise.resolve());
}
component = new Component({
target,
data: Object.assign(data, preloaded),
hydrate: !!component
});
if (scroll) {
window.scrollTo(scroll.x, scroll.y);
}
});
}
function navigate(url, id) {
const selected = select_route(url);
if (selected) {
if (id) {
// popstate or initial navigation
cid = id;
} else {
// clicked on a link. preserve scroll state
scroll_history[cid] = scroll_state();
id = cid = ++uid;
scroll_history[cid] = { x: 0, y: 0 };
history.pushState({ id }, '', url.href);
}
selected.route.load().then(mod => {
render(mod.default, selected.data, scroll_history[id]);
});
cid = id;
return true;
}
}
function handle_click(event) {
// 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 = findAnchor(event.target);
if (!a) 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 = svg ? a.href.baseVal : a.href;
if (href === window.location.href) {
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 has a target
if (svg ? a.target.baseVal : a.target) return;
const url = new URL(href);
// Don't handle hash changes
if (url.pathname === window.location.pathname && url.search === window.location.search) return;
if (navigate(url, null)) {
event.preventDefault();
}
}
function handle_popstate(event) {
scroll_history[cid] = scroll_state();
if (event.state) {
navigate(new URL(window.location), event.state.id);
} else {
// hashchange
cid = ++uid;
history.replaceState({ id: cid }, '', window.location.href);
}
}
function prefetch(event) {
const a = findAnchor(event.target);
if (!a || a.rel !== 'prefetch') return;
const selected = select_route(new URL(a.href));
if (selected) {
selected.route.load().then(mod => {
if (mod.default.preload) mod.default.preload(selected.data);
});
}
}
function findAnchor(node) {
while (node && node.nodeName.toUpperCase() !== 'A') node = node.parentNode; // SVG elements have a lowercase name
return node;
}
let inited;
const app = {
init(_target, _routes) {
target = _target;
routes = _routes;
if (!inited) { // this check makes HMR possible
window.addEventListener('click', handle_click);
window.addEventListener('popstate', handle_popstate);
// prefetch
window.addEventListener('touchstart', prefetch);
window.addEventListener('mouseover', prefetch);
inited = true;
}
const scroll = scroll_history[uid] = scroll_state();
history.replaceState({ id: uid }, '', window.location.href);
navigate(new URL(window.location), uid);
}
};
function which(event) {
event = event || window.event;
return event.which === null ? event.button : event.which;
}
function scroll_state() {
return {
x: window.scrollX,
y: window.scrollY
};
}
export default app;