| 1 | import React, { |
| 2 | startTransition, |
| 3 | useLayoutEffect, |
| 4 | useEffect, |
| 5 | useState, |
| 6 | addTransitionType, |
| 7 | } from 'react'; |
| 8 | |
| 9 | import Chrome from './Chrome.js'; |
| 10 | import Page from './Page.js'; |
| 11 | |
| 12 | const enableNavigationAPI = typeof navigation === 'object'; |
| 13 | |
| 14 | export default function App({assets, initialURL}) { |
| 15 | const [routerState, setRouterState] = useState({ |
| 16 | pendingNav: () => {}, |
| 17 | url: initialURL, |
| 18 | }); |
| 19 | function navigate(url) { |
| 20 | if (enableNavigationAPI) { |
| 21 | window.navigation.navigate(url); |
| 22 | } else { |
| 23 | startTransition(() => { |
| 24 | setRouterState({ |
| 25 | url, |
| 26 | pendingNav() { |
| 27 | window.history.pushState({}, '', url); |
| 28 | }, |
| 29 | }); |
| 30 | }); |
| 31 | } |
| 32 | } |
| 33 | useEffect(() => { |
| 34 | if (enableNavigationAPI) { |
| 35 | window.navigation.addEventListener('navigate', event => { |
| 36 | if (!event.canIntercept) { |
| 37 | return; |
| 38 | } |
| 39 | const navigationType = event.navigationType; |
| 40 | const previousIndex = window.navigation.currentEntry.index; |
| 41 | const newURL = new URL(event.destination.url); |
| 42 | event.intercept({ |
| 43 | handler() { |
| 44 | let promise; |
| 45 | startTransition(() => { |
| 46 | addTransitionType('navigation-' + navigationType); |
| 47 | if (navigationType === 'traverse') { |
| 48 | // For traverse types it's useful to distinguish going back or forward. |
| 49 | const nextIndex = event.destination.index; |
| 50 | if (nextIndex > previousIndex) { |
| 51 | addTransitionType('navigation-forward'); |
| 52 | } else if (nextIndex < previousIndex) { |
| 53 | addTransitionType('navigation-back'); |
| 54 | } |
| 55 | } |
| 56 | promise = new Promise(resolve => { |
| 57 | setRouterState({ |
| 58 | url: newURL.pathname + newURL.search, |
| 59 | pendingNav: resolve, |
| 60 | }); |
| 61 | }); |
| 62 | }); |
| 63 | return promise; |
| 64 | }, |
| 65 | commit: 'after-transition', // plz ship this, browsers |
| 66 | }); |
| 67 | }); |
| 68 | } else { |
| 69 | window.addEventListener('popstate', () => { |
| 70 | // This should not animate because restoration has to be synchronous. |
| 71 | // Even though it's a transition. |
| 72 | startTransition(() => { |
| 73 | setRouterState({ |
| 74 | url: document.location.pathname + document.location.search, |
| 75 | pendingNav() { |
| 76 | // Noop. URL has already updated. |
| 77 | }, |
| 78 | }); |
| 79 | }); |
| 80 | }); |
| 81 | } |
| 82 | }, []); |
| 83 | const pendingNav = routerState.pendingNav; |
| 84 | useLayoutEffect(() => { |
| 85 | pendingNav(); |
| 86 | }, [pendingNav]); |
| 87 | return ( |
| 88 | <Chrome title="Hello World" assets={assets}> |
| 89 | <Page url={routerState.url} navigate={navigate} /> |
| 90 | </Chrome> |
| 91 | ); |
| 92 | } |