Add button to load new replies in web UI (#35210)

app/javascript/mastodon/api.ts

@@ -20,6 +20,50 @@ export const getLinks = (response: AxiosResponse) => {
   return LinkHeader.parse(value);
 };
 
+export interface AsyncRefreshHeader {
+  id: string;
+  retry: number;
+}
+
+const isAsyncRefreshHeader = (obj: object): obj is AsyncRefreshHeader =>
+  'id' in obj && 'retry' in obj;
+
+export const getAsyncRefreshHeader = (
+  response: AxiosResponse,
+): AsyncRefreshHeader | null => {
+  const value = response.headers['mastodon-async-refresh'] as
+    | string
+    | undefined;
+
+  if (!value) {
+    return null;
+  }
+
+  const asyncRefreshHeader: Record<string, unknown> = {};
+
+  value.split(/,\s*/).forEach((pair) => {
+    const [key, val] = pair.split('=', 2);
+
+    let typedValue: string | number;
+
+    if (key && ['id', 'retry'].includes(key) && val) {
+      if (val.startsWith('"')) {
+        typedValue = val.slice(1, -1);
+      } else {
+        typedValue = parseInt(val);
+      }
+
+      asyncRefreshHeader[key] = typedValue;
+    }
+  });
+
+  if (isAsyncRefreshHeader(asyncRefreshHeader)) {
+    return asyncRefreshHeader;
+  }
+
+  return null;
+};
+
 const csrfHeader: RawAxiosRequestHeaders = {};
 
 const setCSRFHeader = () => {
@@ -83,7 +127,7 @@ export default function api(withAuthorization = true) {
   return instance;
 }
 
-type ApiUrl = `v${1 | 2}/${string}`;
+type ApiUrl = `v${1 | '1_alpha' | 2}/${string}`;
 type RequestParamsOrData = Record<string, unknown>;
 
 export async function apiRequest<ApiResponse = unknown>(