perf(frontend): reduce api requests for non-logged-in enviroment (#15001)

* wip

* Update CHANGELOG.md

* wip

packages/frontend/src/pages/user/index.vue

@@ -39,6 +39,7 @@ import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { i18n } from '@/i18n.js';
 import { $i } from '@/account.js';
 import MkHorizontalSwipe from '@/components/MkHorizontalSwipe.vue';
+import { getServerContext } from '@/server-context.js';
 
 const XHome = defineAsyncComponent(() => import('./home.vue'));
 const XTimeline = defineAsyncComponent(() => import('./index.timeline.vue'));
@@ -52,6 +53,8 @@ const XFlashs = defineAsyncComponent(() => import('./flashs.vue'));
 const XGallery = defineAsyncComponent(() => import('./gallery.vue'));
 const XRaw = defineAsyncComponent(() => import('./raw.vue'));
 
+const CTX_USER = getServerContext('user');
+
 const props = withDefaults(defineProps<{
 	acct: string;
 	page?: string;
@@ -61,13 +64,24 @@ const props = withDefaults(defineProps<{
 
 const tab = ref(props.page);
 
-const user = ref<null | Misskey.entities.UserDetailed>(null);
+const user = ref<null | Misskey.entities.UserDetailed>(CTX_USER);
 const error = ref<any>(null);
 
 function fetchUser(): void {
 	if (props.acct == null) return;
+
+	const { username, host } = Misskey.acct.parse(props.acct);
+
+	if (CTX_USER && CTX_USER.username === username && CTX_USER.host === host) {
+		user.value = CTX_USER;
+		return;
+	}
+
 	user.value = null;
-	misskeyApi('users/show', Misskey.acct.parse(props.acct)).then(u => {
+	misskeyApi('users/show', {
+		username,
+		host,
+	}).then(u => {
 		user.value = u;
 	}).catch(err => {
 		error.value = err;