ActionButton: put remote follow behind feature detection

app/soapbox/features/ui/components/action-button.tsx

@@ -105,10 +105,9 @@ const ActionButton = ({ account, actionType, small }: iActionButton) => {
     );
   };
 
-  const empty = <></>;
-
-  if (!me) {
-    // Remote follow
+  /** Render a remote follow button, depending on features. */
+  const renderRemoteFollow = (): JSX.Element | null => {
+    // Remote follow through the API.
     if (features.remoteInteractionsAPI) {
       return (
         <Button
@@ -117,18 +116,36 @@ const ActionButton = ({ account, actionType, small }: iActionButton) => {
           text={intl.formatMessage(messages.follow)}
         />
       );
-    }
-
+    // Pleroma's classic remote follow form.
+    } else if (features.pleromaRemoteFollow) {
       return (
         <form method='POST' action='/main/ostatus'>
-        <input type='hidden' name='nickname' value={account.get('acct')} />
+          <input type='hidden' name='nickname' value={account.acct} />
           <input type='hidden' name='profile' value='' />
           <Button text={intl.formatMessage(messages.remote_follow)} type='submit' />
         </form>
       );
     }
 
-  if (me !== account.get('id')) {
+    return null;
+  };
+
+  /** Render remote follow if federating, otherwise hide the button. */
+  const renderLoggedOut = (): JSX.Element | null => {
+    if (features.federating) {
+      return renderRemoteFollow();
+    }
+
+    return null;
+  };
+
+  const empty = <></>;
+
+  if (!me) {
+    return renderLoggedOut();
+  }
+
+  if (me !== account.id) {
     const isFollowing = account.getIn(['relationship', 'following']);
     const blockedBy = account.getIn(['relationship', 'blocked_by']) as boolean;
 

app/soapbox/utils/features.ts

@@ -356,6 +356,12 @@ const getInstanceFeatures = (instance: Instance) => {
      */
     paginatedContext: v.software === TRUTHSOCIAL,
 
+    /**
+     * Displays a form to follow a user when logged out.
+     * @see POST /main/ostatus
+     */
+    pleromaRemoteFollow: v.software === PLEROMA,
+
     /**
      * Can add polls to statuses.
      * @see POST /api/v1/statuses