From 96c30a6d83d44e70844cd7b59221d7ed005d666a Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Tue, 28 Apr 2020 16:00:41 -0400
Subject: [PATCH] refactor router/content

---
 lib/app/components/Content.js | 48 ++---------------------
 lib/app/composables/router.js | 72 +++++++++++++++++++++++++++++------
 lib/theme-default/Layout.vue  |  8 ++--
 3 files changed, 69 insertions(+), 59 deletions(-)

diff --git a/lib/app/components/Content.js b/lib/app/components/Content.js
index 1b3909be..0642e3a5 100644
--- a/lib/app/components/Content.js
+++ b/lib/app/components/Content.js
@@ -1,49 +1,9 @@
-import { h, shallowRef, watchEffect, inject, nextTick } from 'vue'
-import { RouteSymbol } from '../composables/router'
-import Theme from '/@theme/index'
-
-const NotFound = Theme.NotFound || (() => '404 Not Found')
+import { h } from 'vue'
+import { useRoute } from '../composables/router'
 
 export const Content = {
   setup() {
-    const comp = shallowRef()
-
-    if (typeof window !== 'undefined') {
-      const route = inject(RouteSymbol, {
-        path: '/',
-        scrollPosition: 0
-      })
-
-      watchEffect(() => {
-        const pendingPath = route.path
-        let pagePath = pendingPath.replace(/\.html$/, '')
-        if (pagePath.endsWith('/')) {
-          pagePath += 'index'
-        }
-
-        // awlays force re-fetch content in dev
-        import(`${pagePath}.md?t=${Date.now()}`)
-          .then(async (m) => {
-            if (route.path === pendingPath) {
-              comp.value = m.default
-              await nextTick()
-              window.scrollTo({
-                left: 0,
-                top: route.scrollPosition,
-                behavior: 'auto'
-              })
-            }
-          })
-          .catch((err) => {
-            if (route.path === pendingPath) {
-              comp.value = NotFound
-            }
-          })
-      })
-    } else {
-      // TODO SSR
-    }
-
-    return () => (comp.value ? h(comp.value) : null)
+    const route = useRoute()
+    return () => (route.component ? h(route.component) : null)
   }
 }
diff --git a/lib/app/composables/router.js b/lib/app/composables/router.js
index c8f5e307..171b5613 100644
--- a/lib/app/composables/router.js
+++ b/lib/app/composables/router.js
@@ -1,16 +1,31 @@
-import { reactive, provide } from 'vue'
+import { shallowReactive, provide, inject, nextTick } from 'vue'
+import Theme from '/@theme/index'
+
+const NotFound = Theme.NotFound || (() => '404 Not Found')
 
 /**
- * @type {import('vue').InjectionKey<{ path: string, scrollPosition: number }>}
+ * @typedef {{
+ *   path: string
+ *   component: import('vue').Component | null
+ * }} Route
  */
-export const RouteSymbol = Symbol()
+
+/**
+ * @type {import('vue').InjectionKey<Route>}
+ */
+const RouteSymbol = Symbol()
+
+/**
+ * @returns {Route}
+ */
+const getDefaultRoute = () => ({
+  path: location.pathname,
+  component: null
+})
 
 export function useRouter() {
   const loc = location
-  const route = reactive({
-    path: loc.pathname,
-    scrollPosition: window.scrollY
-  })
+  const route = shallowReactive(getDefaultRoute())
 
   window.addEventListener(
     'click',
@@ -41,8 +56,7 @@ export function useRouter() {
             // save scroll position before changing url
             saveScrollPosition()
             history.pushState(null, '', href)
-            route.path = loc.pathname
-            route.scrollPosition = 0
+            loadPage(route)
           }
         }
       }
@@ -56,12 +70,48 @@ export function useRouter() {
      * @param {*} e
      */
     (e) => {
-      route.path = location.pathname
-      route.scrollPosition = (e.state && e.state.scrollPosition) || 0
+      loadPage(route, (e.state && e.state.scrollPosition) || 0)
     }
   )
 
   provide(RouteSymbol, route)
+
+  loadPage(route)
+}
+
+export function useRoute() {
+  return inject(RouteSymbol) || getDefaultRoute()
+}
+
+/**
+ * @param {Route} route
+ * @param {number} scrollPosition
+ */
+function loadPage(route, scrollPosition = 0) {
+  const pendingPath = (route.path = location.pathname)
+  let pagePath = pendingPath.replace(/\.html$/, '')
+  if (pagePath.endsWith('/')) {
+    pagePath += 'index'
+  }
+
+  // awlays force re-fetch content in dev
+  import(`${pagePath}.md?t=${Date.now()}`)
+    .then(async (m) => {
+      if (route.path === pendingPath) {
+        route.component = m.default
+        await nextTick()
+        window.scrollTo({
+          left: 0,
+          top: scrollPosition,
+          behavior: 'auto'
+        })
+      }
+    })
+    .catch((err) => {
+      if (route.path === pendingPath) {
+        route.component = NotFound
+      }
+    })
 }
 
 function saveScrollPosition() {
diff --git a/lib/theme-default/Layout.vue b/lib/theme-default/Layout.vue
index 6d3124cb..fe44ed1e 100644
--- a/lib/theme-default/Layout.vue
+++ b/lib/theme-default/Layout.vue
@@ -1,10 +1,10 @@
 <template>
   <div class="theme-container">
     <h1>Hello VitePress</h1>
-    <pre>{{ $site }}</pre>
-    <pre>{{ $page }}</pre>
-    <pre>{{ site }}</pre>
-    <pre>{{ page }}</pre>
+    <pre>$site {{ $site }}</pre>
+    <pre>$page {{ $page }}</pre>
+    <pre>useSiteData() {{ site }}</pre>
+    <pre>usePageData() {{ page }}</pre>
     <Content/>
   </div>
 </template>