Add instance fetching hooks

src/api/hooks/instance/useInstanceV1.ts

@@ -0,0 +1,20 @@
+import { useQuery } from '@tanstack/react-query';
+
+import { useApi } from 'soapbox/hooks';
+import { InstanceV1, instanceV1Schema } from 'soapbox/schemas/instance';
+
+/** Get the Instance for the current backend. */
+export function useInstanceV1() {
+  const api = useApi();
+
+  const { data: instance, ...rest } = useQuery<InstanceV1>({
+    queryKey: ['instance', api.baseUrl, 'v1'],
+    queryFn: async () => {
+      const response = await api.get('/api/v1/instance');
+      const data = await response.json();
+      return instanceV1Schema.parse(data);
+    },
+  });
+
+  return { instance, ...rest };
+}

src/api/hooks/instance/useInstanceV2.ts

@@ -0,0 +1,22 @@
+import { useQuery } from '@tanstack/react-query';
+
+import { useApi, useFeatures } from 'soapbox/hooks';
+import { Instance, instanceSchema } from 'soapbox/schemas/instance';
+
+/** Get the Instance for the current backend. */
+export function useInstanceV2() {
+  const api = useApi();
+  const features = useFeatures();
+
+  const { data: instance, ...rest } = useQuery<Instance>({
+    queryKey: ['instance', api.baseUrl, 'v2'],
+    queryFn: async () => {
+      const response = await api.get('/api/v2/instance');
+      const data = await response.json();
+      return instanceSchema.parse(data);
+    },
+    enabled: features.instanceV2,
+  });
+
+  return { instance, ...rest };
+}

src/hooks/useApi.ts

@@ -1,3 +1,5 @@
+import { useMemo } from 'react';
+
 import { MastodonClient } from 'soapbox/api/MastodonClient';
 
 import { useAppSelector } from './useAppSelector';
@@ -8,5 +10,7 @@ export function useApi(): MastodonClient {
   const accessToken = useAppSelector((state) => account ? state.auth.users.get(account.url)?.access_token : undefined);
   const baseUrl = account ? new URL(account.url).origin : location.origin;
 
-  return new MastodonClient(baseUrl, accessToken);
+  return useMemo(() => {
+    return new MastodonClient(baseUrl, accessToken);
+  }, [baseUrl, accessToken]);
 }

src/schemas/instance.ts

@@ -305,5 +305,6 @@ const instanceSchema = z.preprocess((data: any) => {
 }));
 
 type Instance = z.infer<typeof instanceSchema>;
+type InstanceV1 = z.infer<typeof instanceV1Schema>;
 
-export { instanceSchema, Instance };
+export { instanceSchema, Instance, instanceV1Schema, InstanceV1 };