Add listing of followed hashtags (#21773)

* Add followed_tags route.

This at least gets us to the point where the page can actually be
rendered, although it doesn't display any hashtags (yet?).

Attempting to implement #20763.

* Fix minor issues.

* I've got the followed tags data partially working

But the Hashtag component errors for some reason. Something about the
value of the history attribute being invalid.

* Fix a mistake in the code

* Minor change.

* Get the followed hashtags list fully working.

Still need to add the Follow/Unfollow buttons, though.

* Resolve JS linter issues.

* Add pagination logic to followed tags list view.

However, it currently loads further pages immediately on page load, so
that's not ideal. Need to figure that one out.

* Appease the linter.

* Apply suggestions from code review

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Fixes and resolve some other feedback.

* Use set/update instead of setIn/updateIn.

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/mastodon/reducers/followed_tags.js

@@ -0,0 +1,42 @@
+import {
+  FOLLOWED_HASHTAGS_FETCH_REQUEST,
+  FOLLOWED_HASHTAGS_FETCH_SUCCESS,
+  FOLLOWED_HASHTAGS_FETCH_FAIL,
+  FOLLOWED_HASHTAGS_EXPAND_REQUEST,
+  FOLLOWED_HASHTAGS_EXPAND_SUCCESS,
+  FOLLOWED_HASHTAGS_EXPAND_FAIL,
+} from 'mastodon/actions/tags';
+import { Map as ImmutableMap, List as ImmutableList, fromJS } from 'immutable';
+
+const initialState = ImmutableMap({
+  items: ImmutableList(),
+  isLoading: false,
+  next: null,
+});
+
+export default function followed_tags(state = initialState, action) {
+  switch(action.type) {
+  case FOLLOWED_HASHTAGS_FETCH_REQUEST:
+    return state.set('isLoading', true);
+  case FOLLOWED_HASHTAGS_FETCH_SUCCESS:
+    return state.withMutations(map => {
+      map.set('items', fromJS(action.followed_tags));
+      map.set('isLoading', false);
+      map.set('next', action.next);
+    });
+  case FOLLOWED_HASHTAGS_FETCH_FAIL:
+    return state.set('isLoading', false);
+  case FOLLOWED_HASHTAGS_EXPAND_REQUEST:
+    return state.set('isLoading', true);
+  case FOLLOWED_HASHTAGS_EXPAND_SUCCESS:
+    return state.withMutations(map => {
+      map.update('items', set => set.concat(fromJS(action.followed_tags)));
+      map.set('isLoading', false);
+      map.set('next', action.next);
+    });
+  case FOLLOWED_HASHTAGS_EXPAND_FAIL:
+    return state.set('isLoading', false);
+  default:
+    return state;
+  }
+};

app/javascript/mastodon/reducers/index.js

@@ -40,6 +40,7 @@ import picture_in_picture from './picture_in_picture';
 import accounts_map from './accounts_map';
 import history from './history';
 import tags from './tags';
+import followed_tags from './followed_tags';
 
 const reducers = {
   announcements,
@@ -83,6 +84,7 @@ const reducers = {
   picture_in_picture,
   history,
   tags,
+  followed_tags,
 };
 
 export default combineReducers(reducers);