feat: Add "Followers you know" widget to user profiles (#34652)

app/javascript/mastodon/actions/accounts_familiar_followers.ts

@@ -0,0 +1,22 @@
+import { createDataLoadingThunk } from 'mastodon/store/typed_functions';
+
+import { apiGetFamiliarFollowers } from '../api/accounts';
+
+import { importFetchedAccounts } from './importer';
+
+export const fetchAccountsFamiliarFollowers = createDataLoadingThunk(
+  'accounts_familiar_followers/fetch',
+  ({ id }: { id: string }) => apiGetFamiliarFollowers(id),
+  ([data], { dispatch }) => {
+    if (!data) {
+      return null;
+    }
+
+    dispatch(importFetchedAccounts(data.accounts));
+
+    return {
+      id: data.id,
+      accountIds: data.accounts.map((account) => account.id),
+    };
+  },
+);

app/javascript/mastodon/api/accounts.ts

@@ -1,5 +1,8 @@
 import { apiRequestPost, apiRequestGet } from 'mastodon/api';
-import type { ApiAccountJSON } from 'mastodon/api_types/accounts';
+import type {
+  ApiAccountJSON,
+  ApiFamiliarFollowersJSON,
+} from 'mastodon/api_types/accounts';
 import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
 import type { ApiHashtagJSON } from 'mastodon/api_types/tags';
 
@@ -31,3 +34,8 @@ export const apiGetFeaturedTags = (id: string) =>
 
 export const apiGetEndorsedAccounts = (id: string) =>
   apiRequestGet<ApiAccountJSON>(`v1/accounts/${id}/endorsements`);
+
+export const apiGetFamiliarFollowers = (id: string) =>
+  apiRequestGet<ApiFamiliarFollowersJSON>('/v1/accounts/familiar_followers', {
+    id,
+  });

app/javascript/mastodon/api_types/accounts.ts

@@ -54,3 +54,9 @@ export interface ApiMutedAccountJSON extends BaseApiAccountJSON {
 // For now, we have the same type representing both `Account` and `MutedAccount`
 // objects, but we should refactor this in the future.
 export type ApiAccountJSON = ApiMutedAccountJSON;
+
+// See app/serializers/rest/familiar_followers_serializer.rb
+export type ApiFamiliarFollowersJSON = {
+  id: string;
+  accounts: ApiAccountJSON[];
+}[];

app/javascript/mastodon/components/avatar_group.tsx

@@ -1,7 +1,7 @@
+import classNames from 'classnames';
 import { Link } from 'react-router-dom';
 
 import { Avatar } from 'mastodon/components/avatar';
-import { NOTIFICATIONS_GROUP_MAX_AVATARS } from 'mastodon/models/notification_group';
 import { useAppSelector } from 'mastodon/store';
 
 const AvatarWrapper: React.FC<{ accountId: string }> = ({ accountId }) => {
@@ -20,11 +20,14 @@ const AvatarWrapper: React.FC<{ accountId: string }> = ({ accountId }) => {
   );
 };
 
-export const AvatarGroup: React.FC<{ accountIds: string[] }> = ({
+export const AvatarGroup: React.FC<{
-  accountIds,
+  accountIds: string[];
-}) => (
+  compact?: boolean;
-  <div className='notification-group__avatar-group'>
+}> = ({ accountIds, compact = false }) => (
-    {accountIds.slice(0, NOTIFICATIONS_GROUP_MAX_AVATARS).map((accountId) => (
+  <div
+    className={classNames('avatar-group', { 'avatar-group--compact': compact })}
+  >
+    {accountIds.map((accountId) => (
       <AvatarWrapper key={accountId} accountId={accountId} />
     ))}
   </div>

app/javascript/mastodon/features/account_timeline/components/account_header.tsx

@@ -59,6 +59,7 @@ import {
 import { getAccountHidden } from 'mastodon/selectors/accounts';
 import { useAppSelector, useAppDispatch } from 'mastodon/store';
 
+import { FamiliarFollowers } from './familiar_followers';
 import { MemorialNote } from './memorial_note';
 import { MovedNote } from './moved_note';
 
@@ -1022,6 +1023,7 @@ export const AccountHeader: React.FC<{
                   />
                 </NavLink>
               </div>
+              <FamiliarFollowers accountId={accountId} />
             </div>
           )}
         </div>

app/javascript/mastodon/features/account_timeline/components/familiar_followers.tsx

@@ -0,0 +1,84 @@
+import { useEffect } from 'react';
+
+import { FormattedMessage } from 'react-intl';
+
+import { Link } from 'react-router-dom';
+
+import { fetchAccountsFamiliarFollowers } from '@/mastodon/actions/accounts_familiar_followers';
+import { AvatarGroup } from '@/mastodon/components/avatar_group';
+import type { Account } from '@/mastodon/models/account';
+import { getAccountFamiliarFollowers } from '@/mastodon/selectors/accounts';
+import { useAppDispatch, useAppSelector } from '@/mastodon/store';
+
+const AccountLink: React.FC<{ account?: Account }> = ({ account }) => (
+  <Link to={`/@${account?.username}`} data-hover-card-account={account?.id}>
+    {account?.display_name}
+  </Link>
+);
+
+const FamiliarFollowersReadout: React.FC<{ familiarFollowers: Account[] }> = ({
+  familiarFollowers,
+}) => {
+  const messageData = {
+    name1: <AccountLink account={familiarFollowers.at(0)} />,
+    name2: <AccountLink account={familiarFollowers.at(1)} />,
+    othersCount: familiarFollowers.length - 2,
+  };
+
+  if (familiarFollowers.length === 1) {
+    return (
+      <FormattedMessage
+        id='account.familiar_followers_one'
+        defaultMessage='Followed by {name1}'
+        values={messageData}
+      />
+    );
+  } else if (familiarFollowers.length === 2) {
+    return (
+      <FormattedMessage
+        id='account.familiar_followers_two'
+        defaultMessage='Followed by {name1} and {name2}'
+        values={messageData}
+      />
+    );
+  } else {
+    return (
+      <FormattedMessage
+        id='account.familiar_followers_many'
+        defaultMessage='Followed by {name1}, {name2}, and {othersCount, plural, one {# other} other {# others}}'
+        values={messageData}
+      />
+    );
+  }
+};
+
+export const FamiliarFollowers: React.FC<{ accountId: string }> = ({
+  accountId,
+}) => {
+  const dispatch = useAppDispatch();
+  const familiarFollowers = useAppSelector((state) =>
+    getAccountFamiliarFollowers(state, accountId),
+  );
+
+  const hasNoData = familiarFollowers === null;
+
+  useEffect(() => {
+    if (hasNoData) {
+      void dispatch(fetchAccountsFamiliarFollowers({ id: accountId }));
+    }
+  }, [dispatch, accountId, hasNoData]);
+
+  if (hasNoData || familiarFollowers.length === 0) {
+    return null;
+  }
+
+  return (
+    <div className='account__header__familiar-followers'>
+      <AvatarGroup
+        compact
+        accountIds={familiarFollowers.slice(0, 3).map((account) => account.id)}
+      />
+      <FamiliarFollowersReadout familiarFollowers={familiarFollowers} />
+    </div>
+  );
+};

app/javascript/mastodon/features/notifications_v2/components/notification_group_with_status.tsx

@@ -7,12 +7,13 @@ import { HotKeys } from 'react-hotkeys';
 
 import { replyComposeById } from 'mastodon/actions/compose';
 import { navigateToStatus } from 'mastodon/actions/statuses';
+import { AvatarGroup } from 'mastodon/components/avatar_group';
 import type { IconProp } from 'mastodon/components/icon';
 import { Icon } from 'mastodon/components/icon';
 import { RelativeTimestamp } from 'mastodon/components/relative_timestamp';
+import { NOTIFICATIONS_GROUP_MAX_AVATARS } from 'mastodon/models/notification_group';
 import { useAppSelector, useAppDispatch } from 'mastodon/store';
 
-import { AvatarGroup } from './avatar_group';
 import { DisplayedName } from './displayed_name';
 import { EmbeddedStatus } from './embedded_status';
 
@@ -98,7 +99,12 @@ export const NotificationGroupWithStatus: React.FC<{
         <div className='notification-group__main'>
           <div className='notification-group__main__header'>
             <div className='notification-group__main__header__wrapper'>
-              <AvatarGroup accountIds={accountIds} />
+              <AvatarGroup
+                accountIds={accountIds.slice(
+                  0,
+                  NOTIFICATIONS_GROUP_MAX_AVATARS,
+                )}
+              />
 
               {actions && (
                 <div className='notification-group__actions'>{actions}</div>

app/javascript/mastodon/locales/en.json

@@ -28,6 +28,9 @@
   "account.edit_profile": "Edit profile",
   "account.enable_notifications": "Notify me when @{name} posts",
   "account.endorse": "Feature on profile",
+  "account.familiar_followers_many": "Followed by {name1}, {name2}, and {othersCount, plural, one {# other} other {# others}}",
+  "account.familiar_followers_one": "Followed by {name1}",
+  "account.familiar_followers_two": "Followed by {name1} and {name2}",
   "account.featured": "Featured",
   "account.featured.accounts": "Profiles",
   "account.featured.hashtags": "Hashtags",

app/javascript/mastodon/reducers/accounts_familiar_followers.ts

@@ -0,0 +1,19 @@
+import { createReducer } from '@reduxjs/toolkit';
+
+import { fetchAccountsFamiliarFollowers } from '../actions/accounts_familiar_followers';
+
+const initialState: Record<string, string[]> = {};
+
+export const accountsFamiliarFollowersReducer = createReducer(
+  initialState,
+  (builder) => {
+    builder.addCase(
+      fetchAccountsFamiliarFollowers.fulfilled,
+      (state, { payload }) => {
+        if (payload) {
+          state[payload.id] = payload.accountIds;
+        }
+      },
+    );
+  },
+);

app/javascript/mastodon/reducers/index.ts

@@ -4,6 +4,7 @@ import { loadingBarReducer } from 'react-redux-loading-bar';
 import { combineReducers } from 'redux-immutable';
 
 import { accountsReducer } from './accounts';
+import { accountsFamiliarFollowersReducer } from './accounts_familiar_followers';
 import { accountsMapReducer } from './accounts_map';
 import { alertsReducer } from './alerts';
 import announcements from './announcements';
@@ -50,6 +51,7 @@ const reducers = {
   status_lists,
   accounts: accountsReducer,
   accounts_map: accountsMapReducer,
+  accounts_familiar_followers: accountsFamiliarFollowersReducer,
   statuses,
   relationships: relationshipsReducer,
   settings,

app/javascript/mastodon/selectors/accounts.ts

@@ -59,3 +59,16 @@ export const getAccountHidden = createSelector(
     return hidden && !(isSelf || followingOrRequested);
   },
 );
+
+export const getAccountFamiliarFollowers = createSelector(
+  [
+    (state: RootState) => state.accounts,
+    (state: RootState, id: string) => state.accounts_familiar_followers[id],
+  ],
+  (accounts, accounts_familiar_followers) => {
+    if (!accounts_familiar_followers) return null;
+    return accounts_familiar_followers
+      .map((id) => accounts.get(id))
+      .filter((f) => !!f);
+  },
+);

app/javascript/styles/mastodon/components.scss

@@ -2167,6 +2167,25 @@ a .account__avatar {
   cursor: pointer;
 }
 
+.avatar-group {
+  display: flex;
+  gap: 8px;
+  flex-wrap: wrap;
+}
+
+.avatar-group--compact {
+  gap: 0;
+  flex-wrap: nowrap;
+
+  & > :not(:first-child) {
+    margin-inline-start: -8px;
+
+    .account__avatar {
+      box-shadow: 0 0 0 2px var(--background-color);
+    }
+  }
+}
+
 .account__avatar-overlay {
   position: relative;
 
@@ -8119,6 +8138,23 @@ noscript {
       }
     }
   }
+
+  &__familiar-followers {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    margin-block-end: 16px;
+    color: $darker-text-color;
+
+    a:any-link {
+      color: inherit;
+      text-decoration: underline;
+    }
+
+    a:hover {
+      text-decoration: none;
+    }
+  }
 }
 
 .account__contents {
@@ -10439,14 +10475,6 @@ noscript {
     }
   }
 
-  &__avatar-group {
-    display: flex;
-    gap: 8px;
-    height: 28px;
-    overflow-y: hidden;
-    flex-wrap: wrap;
-  }
-
   .status {
     padding: 0;
     border: 0;