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The React Framework
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JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
0 && (module.exports = {
IDLE_LINK_STATUS: null,
PENDING_LINK_STATUS: null,
mountFormInstance: null,
mountLinkInstance: null,
onLinkVisibilityChanged: null,
onNavigationIntent: null,
pingVisibleLinks: null,
setLinkForCurrentNavigation: null,
unmountLinkForCurrentNavigation: null,
unmountPrefetchableInstance: null
});
function _export(target, all) {
for(var name in all)Object.defineProperty(target, name, {
enumerable: true,
get: all[name]
});
}
_export(exports, {
IDLE_LINK_STATUS: function() {
return IDLE_LINK_STATUS;
},
PENDING_LINK_STATUS: function() {
return PENDING_LINK_STATUS;
},
mountFormInstance: function() {
return mountFormInstance;
},
mountLinkInstance: function() {
return mountLinkInstance;
},
onLinkVisibilityChanged: function() {
return onLinkVisibilityChanged;
},
onNavigationIntent: function() {
return onNavigationIntent;
},
pingVisibleLinks: function() {
return pingVisibleLinks;
},
setLinkForCurrentNavigation: function() {
return setLinkForCurrentNavigation;
},
unmountLinkForCurrentNavigation: function() {
return unmountLinkForCurrentNavigation;
},
unmountPrefetchableInstance: function() {
return unmountPrefetchableInstance;
}
});
const _approuterinstance = require("./app-router-instance");
const _approuter = require("./app-router");
const _routerreducertypes = require("./router-reducer/router-reducer-types");
const _segmentcache = require("./segment-cache");
const _react = require("react");
// Tracks the most recently navigated link instance. When null, indicates
// the current navigation was not initiated by a link click.
let linkForMostRecentNavigation = null;
const PENDING_LINK_STATUS = {
pending: true
};
const IDLE_LINK_STATUS = {
pending: false
};
function setLinkForCurrentNavigation(link) {
(0, _react.startTransition)(()=>{
linkForMostRecentNavigation == null ? void 0 : linkForMostRecentNavigation.setOptimisticLinkStatus(IDLE_LINK_STATUS);
link == null ? void 0 : link.setOptimisticLinkStatus(PENDING_LINK_STATUS);
linkForMostRecentNavigation = link;
});
}
function unmountLinkForCurrentNavigation(link) {
if (linkForMostRecentNavigation === link) {
linkForMostRecentNavigation = null;
}
}
// Use a WeakMap to associate a Link instance with its DOM element. This is
// used by the IntersectionObserver to track the link's visibility.
const prefetchable = typeof WeakMap === 'function' ? new WeakMap() : new Map();
// A Set of the currently visible links. We re-prefetch visible links after a
// cache invalidation, or when the current URL changes. It's a separate data
// structure from the WeakMap above because only the visible links need to
// be enumerated.
const prefetchableAndVisible = new Set();
// A single IntersectionObserver instance shared by all <Link> components.
const observer = typeof IntersectionObserver === 'function' ? new IntersectionObserver(handleIntersect, {
rootMargin: '200px'
}) : null;
function observeVisibility(element, instance) {
const existingInstance = prefetchable.get(element);
if (existingInstance !== undefined) {
// This shouldn't happen because each <Link> component should have its own
// anchor tag instance, but it's defensive coding to avoid a memory leak in
// case there's a logical error somewhere else.
unmountPrefetchableInstance(element);
}
// Only track prefetchable links that have a valid prefetch URL
prefetchable.set(element, instance);
if (observer !== null) {
observer.observe(element);
}
}
function coercePrefetchableUrl(href) {
try {
return (0, _approuter.createPrefetchURL)(href);
} catch (e) {
// createPrefetchURL sometimes throws an error if an invalid URL is
// provided, though I'm not sure if it's actually necessary.
// TODO: Consider removing the throw from the inner function, or change it
// to reportError. Or maybe the error isn't even necessary for automatic
// prefetches, just navigations.
const reportErrorFn = typeof reportError === 'function' ? reportError : console.error;
reportErrorFn("Cannot prefetch '" + href + "' because it cannot be converted to a URL.");
return null;
}
}
function mountLinkInstance(element, href, router, kind, prefetchEnabled, setOptimisticLinkStatus) {
if (prefetchEnabled) {
const prefetchURL = coercePrefetchableUrl(href);
if (prefetchURL !== null) {
const instance = {
router,
kind,
isVisible: false,
wasHoveredOrTouched: false,
prefetchTask: null,
cacheVersion: -1,
prefetchHref: prefetchURL.href,
setOptimisticLinkStatus
};
// We only observe the link's visibility if it's prefetchable. For
// example, this excludes links to external URLs.
observeVisibility(element, instance);
return instance;
}
}
// If the link is not prefetchable, we still create an instance so we can
// track its optimistic state (i.e. useLinkStatus).
const instance = {
router,
kind,
isVisible: false,
wasHoveredOrTouched: false,
prefetchTask: null,
cacheVersion: -1,
prefetchHref: null,
setOptimisticLinkStatus
};
return instance;
}
function mountFormInstance(element, href, router, kind) {
const prefetchURL = coercePrefetchableUrl(href);
if (prefetchURL === null) {
// This href is not prefetchable, so we don't track it.
// TODO: We currently observe/unobserve a form every time its href changes.
// For Links, this isn't a big deal because the href doesn't usually change,
// but for forms it's extremely common. We should optimize this.
return;
}
const instance = {
router,
kind,
isVisible: false,
wasHoveredOrTouched: false,
prefetchTask: null,
cacheVersion: -1,
prefetchHref: prefetchURL.href,
setOptimisticLinkStatus: null
};
observeVisibility(element, instance);
}
function unmountPrefetchableInstance(element) {
const instance = prefetchable.get(element);
if (instance !== undefined) {
prefetchable.delete(element);
prefetchableAndVisible.delete(instance);
const prefetchTask = instance.prefetchTask;
if (prefetchTask !== null) {
(0, _segmentcache.cancelPrefetchTask)(prefetchTask);
}
}
if (observer !== null) {
observer.unobserve(element);
}
}
function handleIntersect(entries) {
for (const entry of entries){
// Some extremely old browsers or polyfills don't reliably support
// isIntersecting so we check intersectionRatio instead. (Do we care? Not
// really. But whatever this is fine.)
const isVisible = entry.intersectionRatio > 0;
onLinkVisibilityChanged(entry.target, isVisible);
}
}
function onLinkVisibilityChanged(element, isVisible) {
if (process.env.NODE_ENV !== 'production') {
// Prefetching on viewport is disabled in development for performance
// reasons, because it requires compiling the target page.
// TODO: Investigate re-enabling this.
return;
}
const instance = prefetchable.get(element);
if (instance === undefined) {
return;
}
instance.isVisible = isVisible;
if (isVisible) {
prefetchableAndVisible.add(instance);
} else {
prefetchableAndVisible.delete(instance);
}
rescheduleLinkPrefetch(instance);
}
function onNavigationIntent(element, unstable_upgradeToDynamicPrefetch) {
const instance = prefetchable.get(element);
if (instance === undefined) {
return;
}
// Prefetch the link on hover/touchstart.
if (instance !== undefined) {
instance.wasHoveredOrTouched = true;
if (process.env.__NEXT_DYNAMIC_ON_HOVER && unstable_upgradeToDynamicPrefetch) {
// Switch to a full, dynamic prefetch
instance.kind = _routerreducertypes.PrefetchKind.FULL;
}
rescheduleLinkPrefetch(instance);
}
}
function rescheduleLinkPrefetch(instance) {
const existingPrefetchTask = instance.prefetchTask;
if (!instance.isVisible) {
// Cancel any in-progress prefetch task. (If it already finished then this
// is a no-op.)
if (existingPrefetchTask !== null) {
(0, _segmentcache.cancelPrefetchTask)(existingPrefetchTask);
}
// We don't need to reset the prefetchTask to null upon cancellation; an
// old task object can be rescheduled with reschedulePrefetchTask. This is a
// micro-optimization but also makes the code simpler (don't need to
// worry about whether an old task object is stale).
return;
}
if (!process.env.__NEXT_CLIENT_SEGMENT_CACHE) {
// The old prefetch implementation does not have different priority levels.
// Just schedule a new prefetch task.
prefetchWithOldCacheImplementation(instance);
return;
}
// In the Segment Cache implementation, we assign a higher priority level to
// links that were at one point hovered or touched. Since the queue is last-
// in-first-out, the highest priority Link is whichever one was hovered last.
//
// We also increase the relative priority of links whenever they re-enter the
// viewport, as if they were being scheduled for the first time.
const priority = instance.wasHoveredOrTouched ? _segmentcache.PrefetchPriority.Intent : _segmentcache.PrefetchPriority.Default;
const appRouterState = (0, _approuterinstance.getCurrentAppRouterState)();
if (appRouterState !== null) {
const treeAtTimeOfPrefetch = appRouterState.tree;
if (existingPrefetchTask === null) {
// Initiate a prefetch task.
const nextUrl = appRouterState.nextUrl;
const cacheKey = (0, _segmentcache.createCacheKey)(instance.prefetchHref, nextUrl);
instance.prefetchTask = (0, _segmentcache.schedulePrefetchTask)(cacheKey, treeAtTimeOfPrefetch, instance.kind === _routerreducertypes.PrefetchKind.FULL, priority);
} else {
// We already have an old task object that we can reschedule. This is
// effectively the same as canceling the old task and creating a new one.
(0, _segmentcache.reschedulePrefetchTask)(existingPrefetchTask, treeAtTimeOfPrefetch, instance.kind === _routerreducertypes.PrefetchKind.FULL, priority);
}
// Keep track of the cache version at the time the prefetch was requested.
// This is used to check if the prefetch is stale.
instance.cacheVersion = (0, _segmentcache.getCurrentCacheVersion)();
}
}
function pingVisibleLinks(nextUrl, tree) {
// For each currently visible link, cancel the existing prefetch task (if it
// exists) and schedule a new one. This is effectively the same as if all the
// visible links left and then re-entered the viewport.
//
// This is called when the Next-Url or the base tree changes, since those
// may affect the result of a prefetch task. It's also called after a
// cache invalidation.
const currentCacheVersion = (0, _segmentcache.getCurrentCacheVersion)();
for (const instance of prefetchableAndVisible){
const task = instance.prefetchTask;
if (task !== null && instance.cacheVersion === currentCacheVersion && task.key.nextUrl === nextUrl && task.treeAtTimeOfPrefetch === tree) {
continue;
}
// Something changed. Cancel the existing prefetch task and schedule a
// new one.
if (task !== null) {
(0, _segmentcache.cancelPrefetchTask)(task);
}
const cacheKey = (0, _segmentcache.createCacheKey)(instance.prefetchHref, nextUrl);
const priority = instance.wasHoveredOrTouched ? _segmentcache.PrefetchPriority.Intent : _segmentcache.PrefetchPriority.Default;
instance.prefetchTask = (0, _segmentcache.schedulePrefetchTask)(cacheKey, tree, instance.kind === _routerreducertypes.PrefetchKind.FULL, priority);
instance.cacheVersion = (0, _segmentcache.getCurrentCacheVersion)();
}
}
function prefetchWithOldCacheImplementation(instance) {
// This is the path used when the Segment Cache is not enabled.
if (typeof window === 'undefined') {
return;
}
const doPrefetch = async ()=>{
// note that `appRouter.prefetch()` is currently sync,
// so we have to wrap this call in an async function to be able to catch() errors below.
return instance.router.prefetch(instance.prefetchHref, {
kind: instance.kind
});
};
// Prefetch the page if asked (only in the client)
// We need to handle a prefetch error here since we may be
// loading with priority which can reject but we don't
// want to force navigation since this is only a prefetch
doPrefetch().catch((err)=>{
if (process.env.NODE_ENV !== 'production') {
// rethrow to show invalid URL errors
throw err;
}
});
}
if ((typeof exports.default === 'function' || (typeof exports.default === 'object' && exports.default !== null)) && typeof exports.default.__esModule === 'undefined') {
Object.defineProperty(exports.default, '__esModule', { value: true });
Object.assign(exports.default, exports);
module.exports = exports.default;
}
//# sourceMappingURL=links.js.map