Emoji Reactions(hopefully)

.env.production.sample

@@ -269,6 +269,9 @@ MAX_POLL_OPTIONS=5
 # Maximum allowed poll option characters
 MAX_POLL_OPTION_CHARS=100
 
+# Maximum number of emoji reactions per toot and user (minimum 1)
+MAX_REACTIONS=1
+
 # Maximum image and video/audio upload sizes
 # Units are in bytes
 # 1048576 bytes equals 1 megabyte

app/controllers/api/v1/statuses/reactions_controller.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Api::V1::Statuses::ReactionsController < Api::BaseController
+  include Authorization
+
+  before_action -> { doorkeeper_authorize! :write, :'write:favourites' }
+  before_action :require_user!
+  before_action :set_status
+
+  def create
+    ReactService.new.call(current_account, @status, params[:id])
+    render_empty
+  end
+
+  def destroy
+    UnreactService.new.call(current_account, @status, params[:id])
+    render_empty
+  end
+
+  private
+
+  def set_status
+    @status = Status.find(params[:status_id])
+  end
+end

app/controllers/settings/preferences_controller.rb

@@ -57,6 +57,7 @@ class Settings::PreferencesController < Settings::BaseController
       :setting_use_pending_items,
       :setting_trends,
       :setting_crop_images,
+      :setting_visible_reactions,
       :setting_always_send_emails,
       notification_emails: %i(follow follow_request reblog favourite mention report pending_account trending_tag trending_link trending_status appeal),
       interactions: %i(must_be_follower must_be_following must_be_following_dm)

app/javascript/flavours/glitch/actions/interactions.js

@@ -41,6 +41,16 @@ export const UNBOOKMARK_REQUEST = 'UNBOOKMARKED_REQUEST';
 export const UNBOOKMARK_SUCCESS = 'UNBOOKMARKED_SUCCESS';
 export const UNBOOKMARK_FAIL    = 'UNBOOKMARKED_FAIL';
 
+export const REACTION_UPDATE = 'REACTION_UPDATE';
+
+export const REACTION_ADD_REQUEST = 'REACTION_ADD_REQUEST';
+export const REACTION_ADD_SUCCESS = 'REACTION_ADD_SUCCESS';
+export const REACTION_ADD_FAIL    = 'REACTION_ADD_FAIL';
+
+export const REACTION_REMOVE_REQUEST = 'REACTION_REMOVE_REQUEST';
+export const REACTION_REMOVE_SUCCESS = 'REACTION_REMOVE_SUCCESS';
+export const REACTION_REMOVE_FAIL    = 'REACTION_REMOVE_FAIL';
+
 export function reblog(status, visibility) {
   return function (dispatch, getState) {
     dispatch(reblogRequest(status));
@@ -392,3 +402,75 @@ export function unpinFail(status, error) {
     error,
   };
 };
+
+export const addReaction = (statusId, name, url) => (dispatch, getState) => {
+  const status = getState().get('statuses').get(statusId);
+  let alreadyAdded = false;
+  if (status) {
+    const reaction = status.get('reactions').find(x => x.get('name') === name);
+    if (reaction && reaction.get('me')) {
+      alreadyAdded = true;
+    }
+  }
+  if (!alreadyAdded) {
+    dispatch(addReactionRequest(statusId, name, url));
+  }
+
+  // encodeURIComponent is required for the Keycap Number Sign emoji, see:
+  // <https://github.com/glitch-soc/mastodon/pull/1980#issuecomment-1345538932>
+  api(getState).post(`/api/v1/statuses/${statusId}/react/${encodeURIComponent(name)}`).then(() => {
+    dispatch(addReactionSuccess(statusId, name));
+  }).catch(err => {
+    if (!alreadyAdded) {
+      dispatch(addReactionFail(statusId, name, err));
+    }
+  });
+};
+
+export const addReactionRequest = (statusId, name, url) => ({
+  type: REACTION_ADD_REQUEST,
+  id: statusId,
+  name,
+  url,
+});
+
+export const addReactionSuccess = (statusId, name) => ({
+  type: REACTION_ADD_SUCCESS,
+  id: statusId,
+  name,
+});
+
+export const addReactionFail = (statusId, name, error) => ({
+  type: REACTION_ADD_FAIL,
+  id: statusId,
+  name,
+  error,
+});
+
+export const removeReaction = (statusId, name) => (dispatch, getState) => {
+  dispatch(removeReactionRequest(statusId, name));
+
+  api(getState).post(`/api/v1/statuses/${statusId}/unreact/${encodeURIComponent(name)}`).then(() => {
+    dispatch(removeReactionSuccess(statusId, name));
+  }).catch(err => {
+    dispatch(removeReactionFail(statusId, name, err));
+  });
+};
+
+export const removeReactionRequest = (statusId, name) => ({
+  type: REACTION_REMOVE_REQUEST,
+  id: statusId,
+  name,
+});
+
+export const removeReactionSuccess = (statusId, name) => ({
+  type: REACTION_REMOVE_SUCCESS,
+  id: statusId,
+  name,
+});
+
+export const removeReactionFail = (statusId, name) => ({
+  type: REACTION_REMOVE_FAIL,
+  id: statusId,
+  name,
+});

app/javascript/flavours/glitch/actions/notifications.js

@@ -139,6 +139,7 @@ const excludeTypesFromFilter = filter => {
     'follow',
     'follow_request',
     'favourite',
+    'reaction',
     'reblog',
     'mention',
     'poll',

app/javascript/flavours/glitch/components/status.js

@@ -6,6 +6,7 @@ import StatusHeader from './status_header';
 import StatusIcons from './status_icons';
 import StatusContent from './status_content';
 import StatusActionBar from './status_action_bar';
+import StatusReactions from './status_reactions';
 import AttachmentList from './attachment_list';
 import Card from '../features/status/components/card';
 import { injectIntl, FormattedMessage } from 'react-intl';
@@ -16,7 +17,7 @@ import NotificationOverlayContainer from 'flavours/glitch/features/notifications
 import classNames from 'classnames';
 import { autoUnfoldCW } from 'flavours/glitch/utils/content_warning';
 import PollContainer from 'flavours/glitch/containers/poll_container';
-import { displayMedia } from 'flavours/glitch/initial_state';
+import { displayMedia, visibleReactions } from 'flavours/glitch/initial_state';
 import PictureInPicturePlaceholder from 'flavours/glitch/components/picture_in_picture_placeholder';
 
 // We use the component (and not the container) since we do not want
@@ -61,6 +62,7 @@ class Status extends ImmutablePureComponent {
 
   static contextTypes = {
     router: PropTypes.object,
+    identity: PropTypes.object,
   };
 
   static propTypes = {
@@ -76,6 +78,8 @@ class Status extends ImmutablePureComponent {
     onDelete: PropTypes.func,
     onDirect: PropTypes.func,
     onMention: PropTypes.func,
+    onReactionAdd: PropTypes.func,
+    onReactionRemove: PropTypes.func,
     onPin: PropTypes.func,
     onOpenMedia: PropTypes.func,
     onOpenVideo: PropTypes.func,
@@ -723,6 +727,7 @@ class Status extends ImmutablePureComponent {
     if (this.props.prepend && account) {
       const notifKind = {
         favourite: 'favourited',
+        reaction: 'reacted',
         reblog: 'boosted',
         reblogged_by: 'boosted',
         status: 'posted',
@@ -801,6 +806,15 @@ class Status extends ImmutablePureComponent {
             rewriteMentions={settings.get('rewrite_mentions')}
           />
 
+          <StatusReactions
+            statusId={status.get('id')}
+            reactions={status.get('reactions')}
+            numVisible={visibleReactions}
+            addReaction={this.props.onReactionAdd}
+            removeReaction={this.props.onReactionRemove}
+            canReact={this.context.identity.signedIn}
+          />
+
           {!isCollapsed || !(muted || !settings.getIn(['collapsed', 'show_action_bar'])) ? (
             <StatusActionBar
               status={status}

app/javascript/flavours/glitch/components/status_action_bar.js

@@ -5,11 +5,12 @@ import IconButton from './icon_button';
 import DropdownMenuContainer from 'flavours/glitch/containers/dropdown_menu_container';
 import { defineMessages, injectIntl } from 'react-intl';
 import ImmutablePureComponent from 'react-immutable-pure-component';
-import { me } from 'flavours/glitch/initial_state';
+import { me, maxReactions } from 'flavours/glitch/initial_state';
 import RelativeTimestamp from './relative_timestamp';
 import { accountAdminLink, statusAdminLink } from 'flavours/glitch/utils/backend_links';
 import classNames from 'classnames';
 import { PERMISSION_MANAGE_USERS } from 'flavours/glitch/permissions';
+import EmojiPickerDropdown from '../features/compose/containers/emoji_picker_dropdown_container';
 
 const messages = defineMessages({
   delete: { id: 'status.delete', defaultMessage: 'Delete' },
@@ -29,6 +30,7 @@ const messages = defineMessages({
   cancel_reblog_private: { id: 'status.cancel_reblog_private', defaultMessage: 'Unboost' },
   cannot_reblog: { id: 'status.cannot_reblog', defaultMessage: 'This post cannot be boosted' },
   favourite: { id: 'status.favourite', defaultMessage: 'Favourite' },
+  react: { id: 'status.react', defaultMessage: 'React' },
   bookmark: { id: 'status.bookmark', defaultMessage: 'Bookmark' },
   open: { id: 'status.open', defaultMessage: 'Expand this status' },
   report: { id: 'status.report', defaultMessage: 'Report @{name}' },
@@ -58,6 +60,7 @@ class StatusActionBar extends ImmutablePureComponent {
     status: ImmutablePropTypes.map.isRequired,
     onReply: PropTypes.func,
     onFavourite: PropTypes.func,
+    onReactionAdd: PropTypes.func,
     onReblog: PropTypes.func,
     onQuote: PropTypes.func,
     onDelete: PropTypes.func,
@@ -116,6 +119,10 @@ class StatusActionBar extends ImmutablePureComponent {
     }
   }
 
+  handleEmojiPick = data => {
+    this.props.onReactionAdd(this.props.status.get('id'), data.native.replace(/:/g, ''), data.imageUrl);
+  }
+
   handleReblogClick = e => {
     const { signedIn } = this.context.identity;
 
@@ -208,8 +215,11 @@ class StatusActionBar extends ImmutablePureComponent {
     this.props.onAddFilter(this.props.status);
   }
 
+  handleNoOp = () => {} // hack for reaction add button
+
   render () {
     const { status, intl, withDismiss, withCounters, showReplyCount, scrollKey } = this.props;
+    const { signedIn } = this.context.identity;
 
     const anonymousAccess    = !me;
     const mutingConversation = status.get('muted');
@@ -311,6 +321,17 @@ class StatusActionBar extends ImmutablePureComponent {
       <IconButton className='status__action-bar-button' title={intl.formatMessage(messages.hide)} icon='eye' onClick={this.handleHideClick} />
     );
 
+    const canReact = signedIn && status.get('reactions').filter(r => r.get('count') > 0 && r.get('me')).size < maxReactions;
+    const reactButton = (
+      <IconButton
+        className='status__action-bar-button'
+        onClick={this.handleNoOp} // EmojiPickerDropdown handles that
+        title={intl.formatMessage(messages.react)}
+        disabled={!canReact}
+        icon='plus'
+      />
+    );
+
     return (
       <div className='status__action-bar'>
         <IconButton
@@ -325,6 +346,11 @@ class StatusActionBar extends ImmutablePureComponent {
         <IconButton className='status__action-bar-button' disabled={!publicStatus} title={!publicStatus ? intl.formatMessage(messages.cannot_reblog) : intl.formatMessage(messages.quote)} icon='quote-right' onClick={this.handleQuoteClick} />
 
         <IconButton className='status__action-bar-button star-icon' animate active={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} counter={withCounters ? status.get('favourites_count') : undefined} />
+        {
+          signedIn
+            ? <EmojiPickerDropdown className='status__action-bar-button' onPickEmoji={this.handleEmojiPick} button={reactButton} disabled={!canReact} />
+            : reactButton
+        }
         {shareButton}
         <IconButton className='status__action-bar-button bookmark-icon' disabled={anonymousAccess} active={status.get('bookmarked')} title={intl.formatMessage(messages.bookmark)} icon='bookmark' onClick={this.handleBookmarkClick} />
 

app/javascript/flavours/glitch/components/status_prepend.js

@@ -56,6 +56,14 @@ export default class StatusPrepend extends React.PureComponent {
           values={{ name : link }}
         />
       );
+    case 'reaction':
+      return (
+        <FormattedMessage
+          id='notification.reaction'
+          defaultMessage='{name} reacted to your status'
+          values={{ name: link }}
+        />
+      );
     case 'reblog':
       return (
         <FormattedMessage
@@ -110,6 +118,9 @@ export default class StatusPrepend extends React.PureComponent {
     case 'favourite':
       iconId = 'star';
       break;
+    case 'reaction':
+      iconId = 'plus';
+      break;
     case 'featured':
       iconId = 'thumb-tack';
       break;

app/javascript/flavours/glitch/components/status_reactions.js

@@ -0,0 +1,170 @@
+import ImmutablePureComponent from 'react-immutable-pure-component';
+import PropTypes from 'prop-types';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import { autoPlayGif, reduceMotion } from '../initial_state';
+import spring from 'react-motion/lib/spring';
+import TransitionMotion from 'react-motion/lib/TransitionMotion';
+import classNames from 'classnames';
+import React from 'react';
+import unicodeMapping from '../features/emoji/emoji_unicode_mapping_light';
+import AnimatedNumber from './animated_number';
+import { assetHost } from '../utils/config';
+
+export default class StatusReactions extends ImmutablePureComponent {
+
+  static propTypes = {
+    statusId: PropTypes.string.isRequired,
+    reactions: ImmutablePropTypes.list.isRequired,
+    numVisible: PropTypes.number,
+    addReaction: PropTypes.func.isRequired,
+    canReact: PropTypes.bool.isRequired,
+    removeReaction: PropTypes.func.isRequired,
+  };
+
+  willEnter() {
+    return { scale: reduceMotion ? 1 : 0 };
+  }
+
+  willLeave() {
+    return { scale: reduceMotion ? 0 : spring(0, { stiffness: 170, damping: 26 }) };
+  }
+
+  render() {
+    const { reactions, numVisible } = this.props;
+    let visibleReactions = reactions
+      .filter(x => x.get('count') > 0)
+      .sort((a, b) => b.get('count') - a.get('count'));
+
+    if (numVisible >= 0) {
+      visibleReactions = visibleReactions.filter((_, i) => i < numVisible);
+    }
+
+    const styles = visibleReactions.map(reaction => ({
+      key: reaction.get('name'),
+      data: reaction,
+      style: { scale: reduceMotion ? 1 : spring(1, { stiffness: 150, damping: 13 }) },
+    })).toArray();
+
+    return (
+      <TransitionMotion styles={styles} willEnter={this.willEnter} willLeave={this.willLeave}>
+        {items => (
+          <div className={classNames('reactions-bar', { 'reactions-bar--empty': visibleReactions.isEmpty() })}>
+            {items.map(({ key, data, style }) => (
+              <Reaction
+                key={key}
+                statusId={this.props.statusId}
+                reaction={data}
+                style={{ transform: `scale(${style.scale})`, position: style.scale < 0.5 ? 'absolute' : 'static' }}
+                addReaction={this.props.addReaction}
+                removeReaction={this.props.removeReaction}
+                canReact={this.props.canReact}
+              />
+            ))}
+          </div>
+        )}
+      </TransitionMotion>
+    );
+  }
+
+}
+
+class Reaction extends ImmutablePureComponent {
+
+  static propTypes = {
+    statusId: PropTypes.string,
+    reaction: ImmutablePropTypes.map.isRequired,
+    addReaction: PropTypes.func.isRequired,
+    removeReaction: PropTypes.func.isRequired,
+    canReact: PropTypes.bool.isRequired,
+    style: PropTypes.object,
+  };
+
+  state = {
+    hovered: false,
+  };
+
+  handleClick = () => {
+    const { reaction, statusId, addReaction, removeReaction } = this.props;
+
+    if (reaction.get('me')) {
+      removeReaction(statusId, reaction.get('name'));
+    } else {
+      addReaction(statusId, reaction.get('name'));
+    }
+  }
+
+  handleMouseEnter = () => this.setState({ hovered: true })
+
+  handleMouseLeave = () => this.setState({ hovered: false })
+
+  render() {
+    const { reaction } = this.props;
+
+    return (
+      <button
+        className={classNames('reactions-bar__item', { active: reaction.get('me') })}
+        onClick={this.handleClick}
+        onMouseEnter={this.handleMouseEnter}
+        onMouseLeave={this.handleMouseLeave}
+        disabled={!this.props.canReact}
+        style={this.props.style}
+      >
+        <span className='reactions-bar__item__emoji'>
+          <Emoji
+            hovered={this.state.hovered}
+            emoji={reaction.get('name')}
+            url={reaction.get('url')}
+            staticUrl={reaction.get('static_url')}
+          />
+        </span>
+        <span className='reactions-bar__item__count'>
+          <AnimatedNumber value={reaction.get('count')} />
+        </span>
+      </button>
+    );
+  }
+
+}
+
+class Emoji extends React.PureComponent {
+
+  static propTypes = {
+    emoji: PropTypes.string.isRequired,
+    hovered: PropTypes.bool.isRequired,
+    url: PropTypes.string,
+    staticUrl: PropTypes.string,
+  };
+
+  render() {
+    const { emoji, hovered, url, staticUrl } = this.props;
+
+    if (unicodeMapping[emoji]) {
+      const { filename, shortCode } = unicodeMapping[this.props.emoji];
+      const title = shortCode ? `:${shortCode}:` : '';
+
+      return (
+        <img
+          draggable='false'
+          className='emojione'
+          alt={emoji}
+          title={title}
+          src={`${assetHost}/emoji/${filename}.svg`}
+        />
+      );
+    } else {
+      const filename = (autoPlayGif || hovered) ? url : staticUrl;
+      const shortCode = `:${emoji}:`;
+
+      return (
+        <img
+          draggable='false'
+          className='emojione custom-emoji'
+          alt={shortCode}
+          title={shortCode}
+          src={filename}
+        />
+      );
+    }
+  }
+
+}

app/javascript/flavours/glitch/containers/status_container.js

@@ -1,6 +1,5 @@
 import { connect } from 'react-redux';
 import Status from 'flavours/glitch/components/status';
-import { List as ImmutableList } from 'immutable';
 import { makeGetStatus } from 'flavours/glitch/selectors';
 import {
   replyCompose,
@@ -17,6 +16,8 @@ import {
   unbookmark,
   pin,
   unpin,
+  addReaction,
+  removeReaction,
 } from 'flavours/glitch/actions/interactions';
 import {
   muteStatus,
@@ -186,6 +187,14 @@ const mapDispatchToProps = (dispatch, { intl, contextType }) => ({
     }
   },
 
+  onReactionAdd (statusId, name, url) {
+    dispatch(addReaction(statusId, name, url));
+  },
+
+  onReactionRemove (statusId, name) {
+    dispatch(removeReaction(statusId, name));
+  },
+
   onEmbed (status) {
     dispatch(openModal('EMBED', {
       url: status.get('url'),

app/javascript/flavours/glitch/features/compose/components/emoji_picker_dropdown.js

@@ -321,6 +321,7 @@ class EmojiPickerDropdown extends React.PureComponent {
     onSkinTone: PropTypes.func.isRequired,
     skinTone: PropTypes.number.isRequired,
     button: PropTypes.node,
+    disabled: PropTypes.bool,
   };
 
   state = {
@@ -358,7 +359,7 @@ class EmojiPickerDropdown extends React.PureComponent {
   }
 
   onToggle = (e) => {
-    if (!this.state.loading && (!e.key || e.key === 'Enter')) {
+    if (!this.state.disabled && !this.state.loading && (!e.key || e.key === 'Enter')) {
       if (this.state.active) {
         this.onHideDropdown();
       } else {

app/javascript/flavours/glitch/features/notifications/components/column_settings.js

@@ -116,6 +116,17 @@ export default class ColumnSettings extends React.PureComponent {
           </div>
         </div>
 
+        <div role='group' aria-labelledby='notifications-reaction'>
+          <span id='notifications-reaction' className='column-settings__section'><FormattedMessage id='notifications.column_settings.reaction' defaultMessage='Reactions:' /></span>
+
+          <div className='column-settings__pillbar'>
+            <PillBarButton disabled={browserPermission === 'denied'} prefix='notifications_desktop' settings={settings} settingPath={['alerts', 'reaction']} onChange={onChange} label={alertStr} />
+            {showPushSettings && <PillBarButton prefix='notifications_push' settings={pushSettings} settingPath={['alerts', 'reaction']} onChange={this.onPushChange} label={pushStr} />}
+            <PillBarButton prefix='notifications' settings={settings} settingPath={['shows', 'reaction']} onChange={onChange} label={showStr} />
+            <PillBarButton prefix='notifications' settings={settings} settingPath={['sounds', 'reaction']} onChange={onChange} label={soundStr} />
+          </div>
+        </div>
+
         <div role='group' aria-labelledby='notifications-mention'>
           <span id='notifications-mention' className='column-settings__section'><FormattedMessage id='notifications.column_settings.mention' defaultMessage='Mentions:' /></span>
 

app/javascript/flavours/glitch/features/notifications/components/filter_bar.js

@@ -6,6 +6,7 @@ import Icon from 'flavours/glitch/components/icon';
 const tooltips = defineMessages({
   mentions: { id: 'notifications.filter.mentions', defaultMessage: 'Mentions' },
   favourites: { id: 'notifications.filter.favourites', defaultMessage: 'Favourites' },
+  reactions: { id: 'notifications.filter.reactions', defaultMessage: 'Reactions' },
   boosts: { id: 'notifications.filter.boosts', defaultMessage: 'Boosts' },
   polls: { id: 'notifications.filter.polls', defaultMessage: 'Poll results' },
   follows: { id: 'notifications.filter.follows', defaultMessage: 'Follows' },
@@ -74,6 +75,13 @@ class FilterBar extends React.PureComponent {
         >
           <Icon id='star' fixedWidth />
         </button>
+        <button
+          className={selectedFilter === 'reaction' ? 'active' : ''}
+          onClick={this.onClick('reaction')}
+          title={intl.formatMessage(tooltips.reactions)}
+        >
+          <Icon id='plus' fixedWidth />
+        </button>
         <button
           className={selectedFilter === 'reblog' ? 'active' : ''}
           onClick={this.onClick('reblog')}

app/javascript/flavours/glitch/features/notifications/components/notification.js

@@ -155,6 +155,28 @@ export default class Notification extends ImmutablePureComponent {
           unread={this.props.unread}
         />
       );
+    case 'reaction':
+      return (
+        <StatusContainer
+          containerId={notification.get('id')}
+          hidden={hidden}
+          id={notification.get('status')}
+          account={notification.get('account')}
+          prepend='reaction'
+          muted
+          notification={notification}
+          onMoveDown={onMoveDown}
+          onMoveUp={onMoveUp}
+          onMention={onMention}
+          getScrollPosition={getScrollPosition}
+          updateScrollBottom={updateScrollBottom}
+          cachedMediaWidth={this.props.cachedMediaWidth}
+          cacheMediaWidth={this.props.cacheMediaWidth}
+          onUnmount={this.props.onUnmount}
+          withDismiss
+          unread={this.props.unread}
+        />
+      );
     case 'reblog':
       return (
         <StatusContainer

app/javascript/flavours/glitch/features/status/components/action_bar.js

@@ -4,10 +4,11 @@ import IconButton from 'flavours/glitch/components/icon_button';
 import ImmutablePropTypes from 'react-immutable-proptypes';
 import DropdownMenuContainer from 'flavours/glitch/containers/dropdown_menu_container';
 import { defineMessages, injectIntl } from 'react-intl';
-import { me } from 'flavours/glitch/initial_state';
+import { me, maxReactions } from 'flavours/glitch/initial_state';
 import { accountAdminLink, statusAdminLink } from 'flavours/glitch/utils/backend_links';
 import classNames from 'classnames';
 import { PERMISSION_MANAGE_USERS } from 'flavours/glitch/permissions';
+import EmojiPickerDropdown from '../../compose/containers/emoji_picker_dropdown_container';
 
 const messages = defineMessages({
   delete: { id: 'status.delete', defaultMessage: 'Delete' },
@@ -22,6 +23,7 @@ const messages = defineMessages({
   cancel_reblog_private: { id: 'status.cancel_reblog_private', defaultMessage: 'Unboost' },
   cannot_reblog: { id: 'status.cannot_reblog', defaultMessage: 'This post cannot be boosted' },
   favourite: { id: 'status.favourite', defaultMessage: 'Favourite' },
+  react: { id: 'status.react', defaultMessage: 'React' },
   bookmark: { id: 'status.bookmark', defaultMessage: 'Bookmark' },
   more: { id: 'status.more', defaultMessage: 'More' },
   mute: { id: 'status.mute', defaultMessage: 'Mute @{name}' },
@@ -52,6 +54,7 @@ class ActionBar extends React.PureComponent {
     onReply: PropTypes.func.isRequired,
     onReblog: PropTypes.func.isRequired,
     onFavourite: PropTypes.func.isRequired,
+    onReactionAdd: PropTypes.func.isRequired,
     onBookmark: PropTypes.func.isRequired,
     onQuote: PropTypes.func.isRequired,
     onMute: PropTypes.func,
@@ -79,6 +82,10 @@ class ActionBar extends React.PureComponent {
     this.props.onFavourite(this.props.status, e);
   }
 
+  handleEmojiPick = data => {
+    this.props.onReactionAdd(this.props.status.get('id'), data.native.replace(/:/g, ''), data.imageUrl);
+  }
+
   handleBookmarkClick = (e) => {
     this.props.onBookmark(this.props.status, e);
   }
@@ -143,6 +150,8 @@ class ActionBar extends React.PureComponent {
     navigator.clipboard.writeText(url);
   }
 
+  handleNoOp = () => {} // hack for reaction add button
+
   render () {
     const { status, intl } = this.props;
     const { signedIn, permissions } = this.context.identity;
@@ -200,6 +209,17 @@ class ActionBar extends React.PureComponent {
       }
     }
 
+    const canReact = signedIn && status.get('reactions').filter(r => r.get('count') > 0 && r.get('me')).size < maxReactions;
+    const reactButton = (
+      <IconButton
+        className='plus-icon'
+        onClick={this.handleNoOp} // EmojiPickerDropdown handles that
+        title={intl.formatMessage(messages.react)}
+        disabled={!canReact}
+        icon='plus'
+      />
+    );
+
     const shareButton = ('share' in navigator) && publicStatus && (
       <div className='detailed-status__button'><IconButton title={intl.formatMessage(messages.share)} icon='share-alt' onClick={this.handleShare} /></div>
     );
@@ -223,6 +243,13 @@ class ActionBar extends React.PureComponent {
         <div className='detailed-status__button'><IconButton className={classNames({ reblogPrivate })} disabled={!publicStatus && !reblogPrivate} active={status.get('reblogged')} title={reblogTitle} icon='retweet' onClick={this.handleReblogClick} /></div>
         <div className='detailed-status__button'><IconButton className='quote-right-icon' disabled={!publicStatus} title={intl.formatMessage(messages.quote)} icon='quote-right' onClick={this.handleQuoteClick} /></div>
         <div className='detailed-status__button'><IconButton className='star-icon' animate active={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} /></div>
+        <div className='detailed-status__button'>
+          {
+            signedIn
+              ? <EmojiPickerDropdown onPickEmoji={this.handleEmojiPick} button={reactButton} disabled={!canReact} />
+              : reactButton
+          }
+        </div>
         {shareButton}
         <div className='detailed-status__button'><IconButton className='bookmark-icon' disabled={!signedIn} active={status.get('bookmarked')} title={intl.formatMessage(messages.bookmark)} icon='bookmark' onClick={this.handleBookmarkClick} /></div>
 

app/javascript/flavours/glitch/features/status/components/detailed_status.js

@@ -20,12 +20,14 @@ import Icon from 'flavours/glitch/components/icon';
 import AnimatedNumber from 'flavours/glitch/components/animated_number';
 import PictureInPicturePlaceholder from 'flavours/glitch/components/picture_in_picture_placeholder';
 import EditedTimestamp from 'flavours/glitch/components/edited_timestamp';
+import StatusReactions from 'flavours/glitch/components/status_reactions';
 
 export default @injectIntl
 class DetailedStatus extends ImmutablePureComponent {
 
   static contextTypes = {
     router: PropTypes.object,
+    identity: PropTypes.object,
   };
 
   static propTypes = {
@@ -43,6 +45,8 @@ class DetailedStatus extends ImmutablePureComponent {
     showMedia: PropTypes.bool,
     usingPiP: PropTypes.bool,
     onToggleMediaVisibility: PropTypes.func,
+    onReactionAdd: PropTypes.func.isRequired,
+    onReactionRemove: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
   };
 
@@ -319,6 +323,14 @@ class DetailedStatus extends ImmutablePureComponent {
             disabled
           />
 
+          <StatusReactions
+            statusId={status.get('id')}
+            reactions={status.get('reactions')}
+            addReaction={this.props.onReactionAdd}
+            removeReaction={this.props.onReactionRemove}
+            canReact={this.context.identity.signedIn}
+          />
+
           <div className='detailed-status__meta'>
             <a className='detailed-status__datetime' href={status.get('url')} target='_blank' rel='noopener noreferrer'>
               <FormattedDate value={new Date(status.get('created_at'))} hour12={false} year='numeric' month='short' day='2-digit' hour='2-digit' minute='2-digit' />

app/javascript/flavours/glitch/features/status/index.js

@@ -20,6 +20,8 @@ import {
   unreblog,
   pin,
   unpin,
+  addReaction,
+  removeReaction,
 } from 'flavours/glitch/actions/interactions';
 import {
   replyCompose,
@@ -292,6 +294,19 @@ class Status extends ImmutablePureComponent {
     }
   }
 
+  handleReactionAdd = (statusId, name, url) => {
+    const { dispatch } = this.props;
+    const { signedIn } = this.context.identity;
+
+    if (signedIn) {
+      dispatch(addReaction(statusId, name, url));
+    }
+  }
+
+  handleReactionRemove = (statusId, name) => {
+    this.props.dispatch(removeReaction(statusId, name));
+  }
+
   handlePin = (status) => {
     if (status.get('pinned')) {
       this.props.dispatch(unpin(status));
@@ -692,6 +707,8 @@ class Status extends ImmutablePureComponent {
                   settings={settings}
                   onOpenVideo={this.handleOpenVideo}
                   onOpenMedia={this.handleOpenMedia}
+                  onReactionAdd={this.handleReactionAdd}
+                  onReactionRemove={this.handleReactionRemove}
                   expanded={isExpanded}
                   onToggleHidden={this.handleToggleHidden}
                   onTranslate={this.handleTranslate}
@@ -706,6 +723,7 @@ class Status extends ImmutablePureComponent {
                   status={status}
                   onReply={this.handleReplyClick}
                   onFavourite={this.handleFavouriteClick}
+                  onReactionAdd={this.handleReactionAdd}
                   onReblog={this.handleReblogClick}
                   onBookmark={this.handleBookmarkClick}
                   onQuote={this.handleQuoteClick}

app/javascript/flavours/glitch/initial_state.js

@@ -61,6 +61,7 @@
  * @property {boolean} limited_federation_mode
  * @property {string} locale
  * @property {string | null} mascot
+ * @property {number} max_reactions
  * @property {string=} me
  * @property {string=} moved_to_account_id
  * @property {string=} owner
@@ -79,6 +80,7 @@
  * @property {boolean} use_blurhash
  * @property {boolean=} use_pending_items
  * @property {string} version
+ * @property {number} visible_reactions
  * @property {boolean} translation_enabled
  * @property {object} local_settings
  */
@@ -121,6 +123,7 @@ export const expandSpoilers = getMeta('expand_spoilers');
 export const forceSingleColumn = !getMeta('advanced_layout');
 export const limitedFederationMode = getMeta('limited_federation_mode');
 export const mascot = getMeta('mascot');
+export const maxReactions = (initialState && initialState.max_reactions) || 1;
 export const me = getMeta('me');
 export const movedToAccountId = getMeta('moved_to_account_id');
 export const owner = getMeta('owner');
@@ -138,6 +141,7 @@ export const unfollowModal = getMeta('unfollow_modal');
 export const useBlurhash = getMeta('use_blurhash');
 export const usePendingItems = getMeta('use_pending_items');
 export const version = getMeta('version');
+export const visibleReactions = getMeta('visible_reactions');
 export const translationEnabled = getMeta('translation_enabled');
 export const languages = initialState?.languages;
 

app/javascript/flavours/glitch/locales/de.json

@@ -71,11 +71,13 @@
   "navigation_bar.keyboard_shortcuts": "Tastaturkürzel",
   "navigation_bar.misc": "Sonstiges",
   "notification.markForDeletion": "Zum Entfernen auswählen",
+  "notification.reaction": "{name} hat auf deinen Beitrag reagiert",
   "notification_purge.btn_all": "Alle\nauswählen",
   "notification_purge.btn_apply": "Ausgewählte\nentfernen",
   "notification_purge.btn_invert": "Auswahl\numkehren",
   "notification_purge.btn_none": "Auswahl\naufheben",
   "notification_purge.start": "Benachrichtigungen-Aufräumen-Modus starten",
+  "notifications.column_settings.reaction": "Reaktionen:",
   "notifications.marked_clear": "Ausgewählte Benachrichtigungen entfernen",
   "notifications.marked_clear_confirmation": "Möchtest du wirklich alle auswählten Benachrichtigungen für immer entfernen?",
   "onboarding.done": "Fertig",
@@ -185,8 +187,10 @@
   "status.in_reply_to": "Dieser Toot ist eine Antwort",
   "status.is_poll": "Dieser Toot ist eine Umfrage",
   "status.local_only": "Nur auf deiner Instanz sichtbar",
+  "status.react": "Reagieren",
   "status.sensitive_toggle": "Zum Anzeigen klicken",
   "status.uncollapse": "Ausklappen",
+  "tooltips.reactions": "Reaktionen",
   "web_app_crash.change_your_settings": "Deine {settings} ändern",
   "web_app_crash.content": "Du kannst folgende Dinge ausprobieren:",
   "web_app_crash.debug_info": "Debug-Informationen",

app/javascript/flavours/glitch/locales/fr.json

@@ -76,6 +76,8 @@
   "notification_purge.btn_invert": "Inverser\nla sélection",
   "notification_purge.btn_none": "Annuler\nla sélection",
   "notification_purge.start": "Activer le mode de nettoyage des notifications",
+  "notification.reaction": "{name} a réagi·e à votre message",
+  "notifications.column_settings.reaction": "Réactions:",
   "notifications.marked_clear": "Effacer les notifications sélectionnées",
   "notifications.marked_clear_confirmation": "Voulez-vous vraiment effacer de manière permanente toutes les notifications sélectionnées ?",
   "onboarding.done": "Terminé",
@@ -185,8 +187,10 @@
   "status.in_reply_to": "Ce post est une réponse",
   "status.is_poll": "Ce post est un sondage",
   "status.local_only": "Visible uniquement depuis votre instance",
+  "status.react": "Réagir",
   "status.sensitive_toggle": "Cliquer pour voir",
   "status.uncollapse": "Déplier",
+  "tooltips.reactions": "Réactions",
   "web_app_crash.change_your_settings": "Changez vos {settings}",
   "web_app_crash.content": "Voici les différentes options qui s'offrent à vous :",
   "web_app_crash.debug_info": "Informations de débogage",

app/javascript/flavours/glitch/reducers/settings.js

@@ -37,6 +37,7 @@ const initialState = ImmutableMap({
       follow: false,
       follow_request: false,
       favourite: false,
+      reaction: false,
       reblog: false,
       mention: false,
       poll: false,
@@ -60,6 +61,7 @@ const initialState = ImmutableMap({
       follow_request: false,
       favourite: true,
       reblog: true,
+      reaction: true,
       mention: true,
       poll: true,
       status: true,
@@ -73,6 +75,7 @@ const initialState = ImmutableMap({
       follow_request: false,
       favourite: true,
       reblog: true,
+      reaction: true,
       mention: true,
       poll: true,
       status: true,

app/javascript/flavours/glitch/reducers/statuses.js

@@ -6,6 +6,11 @@ import {
   UNFAVOURITE_SUCCESS,
   BOOKMARK_REQUEST,
   BOOKMARK_FAIL,
+  REACTION_UPDATE,
+  REACTION_ADD_FAIL,
+  REACTION_REMOVE_FAIL,
+  REACTION_ADD_REQUEST,
+  REACTION_REMOVE_REQUEST,
 } from 'flavours/glitch/actions/interactions';
 import {
   STATUS_MUTE_SUCCESS,
@@ -37,6 +42,43 @@ const deleteStatus = (state, id, references) => {
   return state.delete(id);
 };
 
+const updateReaction = (state, id, name, updater) => state.update(
+  id,
+  status => status.update(
+    'reactions',
+    reactions => {
+      const index = reactions.findIndex(reaction => reaction.get('name') === name);
+      if (index > -1) {
+        return reactions.update(index, reaction => updater(reaction));
+      } else {
+        return reactions.push(updater(fromJS({ name, count: 0 })));
+      }
+    },
+  ),
+);
+
+const updateReactionCount = (state, reaction) => updateReaction(state, reaction.status_id, reaction.name, x => x.set('count', reaction.count));
+
+// The url parameter is only used when adding a new custom emoji reaction
+// (one that wasn't in the reactions list before) because we don't have its
+// URL yet.  In all other cases, it's undefined.
+const addReaction = (state, id, name, url) => updateReaction(
+  state,
+  id,
+  name,
+  x => x.set('me', true)
+    .update('count', n => n + 1)
+    .update('url', old => old ? old : url)
+    .update('static_url', old => old ? old : url),
+);
+
+const removeReaction = (state, id, name) => updateReaction(
+  state,
+  id,
+  name,
+  x => x.set('me', false).update('count', n => n - 1),
+);
+
 const initialState = ImmutableMap();
 
 export default function statuses(state = initialState, action) {
@@ -63,6 +105,14 @@ export default function statuses(state = initialState, action) {
     return state.setIn([action.status.get('id'), 'reblogged'], true);
   case REBLOG_FAIL:
     return state.get(action.status.get('id')) === undefined ? state : state.setIn([action.status.get('id'), 'reblogged'], false);
+  case REACTION_UPDATE:
+    return updateReactionCount(state, action.reaction);
+  case REACTION_ADD_REQUEST:
+  case REACTION_REMOVE_FAIL:
+    return addReaction(state, action.id, action.name, action.url);
+  case REACTION_REMOVE_REQUEST:
+  case REACTION_ADD_FAIL:
+    return removeReaction(state, action.id, action.name);
   case STATUS_MUTE_SUCCESS:
     return state.setIn([action.id, 'muted'], true);
   case STATUS_UNMUTE_SUCCESS:

app/javascript/flavours/glitch/styles/components/accounts.scss

@@ -306,6 +306,10 @@
   text-align: center;
 }
 
+.detailed-status__button .emoji-button {
+  padding: 0;
+}
+
 .relationship-tag {
   color: $primary-text-color;
   margin-bottom: 4px;

app/javascript/flavours/glitch/styles/components/status.scss

@@ -440,6 +440,10 @@
   .notification__message {
     margin: -10px 0px 10px 0;
   }
+
+  .reactions-bar--empty {
+    display: none;
+  }
 }
 
 .notification-favourite {
@@ -584,6 +588,10 @@
   align-items: center;
   display: flex;
   margin-top: 8px;
+
+  & > .emoji-picker-dropdown > .emoji-button {
+    padding: 0;
+  }
 }
 
 .status__action-bar-button {
@@ -592,6 +600,10 @@
   &.icon-button--with-counter {
     margin-right: 14px;
   }
+
+  .fa-plus {
+    padding-top: 1px;
+  }
 }
 
 .status__action-bar-dropdown {
@@ -658,6 +670,10 @@
   display: flex;
   flex-direction: row;
   padding: 10px 0;
+
+  .fa-plus {
+    padding-top: 2px;
+  }
 }
 
 .detailed-status__link {

app/javascript/mastodon/actions/interactions.js

@@ -41,6 +41,16 @@ export const UNBOOKMARK_REQUEST = 'UNBOOKMARKED_REQUEST';
 export const UNBOOKMARK_SUCCESS = 'UNBOOKMARKED_SUCCESS';
 export const UNBOOKMARK_FAIL    = 'UNBOOKMARKED_FAIL';
 
+export const REACTION_UPDATE = 'REACTION_UPDATE';
+
+export const REACTION_ADD_REQUEST = 'REACTION_ADD_REQUEST';
+export const REACTION_ADD_SUCCESS = 'REACTION_ADD_SUCCESS';
+export const REACTION_ADD_FAIL    = 'REACTION_ADD_FAIL';
+
+export const REACTION_REMOVE_REQUEST = 'REACTION_REMOVE_REQUEST';
+export const REACTION_REMOVE_SUCCESS = 'REACTION_REMOVE_SUCCESS';
+export const REACTION_REMOVE_FAIL    = 'REACTION_REMOVE_FAIL';
+
 export function reblog(status, visibility) {
   return function (dispatch, getState) {
     dispatch(reblogRequest(status));
@@ -412,3 +422,75 @@ export function unpinFail(status, error) {
     skipLoading: true,
   };
 }
+
+export const addReaction = (statusId, name, url) => (dispatch, getState) => {
+  const status = getState().get('statuses').get(statusId);
+  let alreadyAdded = false;
+  if (status) {
+    const reaction = status.get('reactions').find(x => x.get('name') === name);
+    if (reaction && reaction.get('me')) {
+      alreadyAdded = true;
+    }
+  }
+  if (!alreadyAdded) {
+    dispatch(addReactionRequest(statusId, name, url));
+  }
+
+  // encodeURIComponent is required for the Keycap Number Sign emoji, see:
+  // <https://github.com/glitch-soc/mastodon/pull/1980#issuecomment-1345538932>
+  api(getState).post(`/api/v1/statuses/${statusId}/react/${encodeURIComponent(name)}`).then(() => {
+    dispatch(addReactionSuccess(statusId, name));
+  }).catch(err => {
+    if (!alreadyAdded) {
+      dispatch(addReactionFail(statusId, name, err));
+    }
+  });
+};
+
+export const addReactionRequest = (statusId, name, url) => ({
+  type: REACTION_ADD_REQUEST,
+  id: statusId,
+  name,
+  url,
+});
+
+export const addReactionSuccess = (statusId, name) => ({
+  type: REACTION_ADD_SUCCESS,
+  id: statusId,
+  name,
+});
+
+export const addReactionFail = (statusId, name, error) => ({
+  type: REACTION_ADD_FAIL,
+  id: statusId,
+  name,
+  error,
+});
+
+export const removeReaction = (statusId, name) => (dispatch, getState) => {
+  dispatch(removeReactionRequest(statusId, name));
+
+  api(getState).post(`/api/v1/statuses/${statusId}/unreact/${encodeURIComponent(name)}`).then(() => {
+    dispatch(removeReactionSuccess(statusId, name));
+  }).catch(err => {
+    dispatch(removeReactionFail(statusId, name, err));
+  });
+};
+
+export const removeReactionRequest = (statusId, name) => ({
+  type: REACTION_REMOVE_REQUEST,
+  id: statusId,
+  name,
+});
+
+export const removeReactionSuccess = (statusId, name) => ({
+  type: REACTION_REMOVE_SUCCESS,
+  id: statusId,
+  name,
+});
+
+export const removeReactionFail = (statusId, name) => ({
+  type: REACTION_REMOVE_FAIL,
+  id: statusId,
+  name,
+});

app/javascript/mastodon/actions/notifications.js

@@ -127,6 +127,7 @@ const excludeTypesFromFilter = filter => {
     'follow',
     'follow_request',
     'favourite',
+    'reaction',
     'reblog',
     'mention',
     'poll',

app/javascript/mastodon/components/status.js

@@ -7,6 +7,7 @@ import RelativeTimestamp from './relative_timestamp';
 import DisplayName from './display_name';
 import StatusContent from './status_content';
 import StatusActionBar from './status_action_bar';
+import StatusReactions from './status_reactions';
 import AttachmentList from './attachment_list';
 import Card from '../features/status/components/card';
 import { injectIntl, defineMessages, FormattedMessage } from 'react-intl';
@@ -15,7 +16,7 @@ import { MediaGallery, Video, Audio } from '../features/ui/util/async-components
 import { HotKeys } from 'react-hotkeys';
 import classNames from 'classnames';
 import Icon from 'mastodon/components/icon';
-import { displayMedia } from '../initial_state';
+import { displayMedia, visibleReactions } from '../initial_state';
 import PictureInPicturePlaceholder from 'mastodon/components/picture_in_picture_placeholder';
 
 // We use the component (and not the container) since we do not want
@@ -64,6 +65,7 @@ class Status extends ImmutablePureComponent {
 
   static contextTypes = {
     router: PropTypes.object,
+    identity: PropTypes.object,
   };
 
   static propTypes = {
@@ -76,6 +78,8 @@ class Status extends ImmutablePureComponent {
     onDelete: PropTypes.func,
     onDirect: PropTypes.func,
     onMention: PropTypes.func,
+    onReactionAdd: PropTypes.func,
+    onReactionRemove: PropTypes.func,
     onPin: PropTypes.func,
     onOpenMedia: PropTypes.func,
     onOpenVideo: PropTypes.func,
@@ -99,6 +103,7 @@ class Status extends ImmutablePureComponent {
     cachedMediaWidth: PropTypes.number,
     scrollKey: PropTypes.string,
     deployPictureInPicture: PropTypes.func,
+    emojiMap: ImmutablePropTypes.map.isRequired,
     pictureInPicture: ImmutablePropTypes.contains({
       inUse: PropTypes.bool,
       available: PropTypes.bool,
@@ -537,6 +542,15 @@ class Status extends ImmutablePureComponent {
 
             {media}
 
+            <StatusReactions
+              statusId={status.get('id')}
+              reactions={status.get('reactions')}
+              numVisible={visibleReactions}
+              addReaction={this.props.onReactionAdd}
+              removeReaction={this.props.onReactionRemove}
+              canReact={this.context.identity.signedIn}
+            />
+
             <StatusActionBar scrollKey={scrollKey} status={status} account={account} onFilter={matchedFilters ? this.handleFilterClick : null} {...other} />
           </div>
         </div>

app/javascript/mastodon/components/status_action_bar.js

@@ -6,9 +6,10 @@ import IconButton from './icon_button';
 import DropdownMenuContainer from '../containers/dropdown_menu_container';
 import { defineMessages, injectIntl } from 'react-intl';
 import ImmutablePureComponent from 'react-immutable-pure-component';
-import { me } from '../initial_state';
+import { me, maxReactions } from '../initial_state';
 import classNames from 'classnames';
 import { PERMISSION_MANAGE_USERS } from 'mastodon/permissions';
+import EmojiPickerDropdown from '../features/compose/containers/emoji_picker_dropdown_container';
 
 const messages = defineMessages({
   delete: { id: 'status.delete', defaultMessage: 'Delete' },
@@ -27,6 +28,7 @@ const messages = defineMessages({
   cancel_reblog_private: { id: 'status.cancel_reblog_private', defaultMessage: 'Unboost' },
   cannot_reblog: { id: 'status.cannot_reblog', defaultMessage: 'This post cannot be boosted' },
   favourite: { id: 'status.favourite', defaultMessage: 'Favourite' },
+  react: { id: 'status.react', defaultMessage: 'React' },
   bookmark: { id: 'status.bookmark', defaultMessage: 'Bookmark' },
   removeBookmark: { id: 'status.remove_bookmark', defaultMessage: 'Remove bookmark' },
   open: { id: 'status.open', defaultMessage: 'Expand this status' },
@@ -66,6 +68,7 @@ class StatusActionBar extends ImmutablePureComponent {
     relationship: ImmutablePropTypes.map,
     onReply: PropTypes.func,
     onFavourite: PropTypes.func,
+    onReactionAdd: PropTypes.func,
     onReblog: PropTypes.func,
     onDelete: PropTypes.func,
     onDirect: PropTypes.func,
@@ -127,6 +130,10 @@ class StatusActionBar extends ImmutablePureComponent {
     }
   }
 
+  handleEmojiPick = data => {
+      this.props.onReactionAdd(this.props.status.get('id'), data.native.replace(/:/g, ''), data.imageUrl);
+  }
+
   handleReblogClick = e => {
     const { signedIn } = this.context.identity;
 
@@ -230,6 +237,8 @@ class StatusActionBar extends ImmutablePureComponent {
     this.props.onFilter();
   }
 
+  handleNoOp = () => {} // hack for reaction add button
+
   render () {
     const { status, relationship, intl, withDismiss, withCounters, scrollKey } = this.props;
     const { signedIn } = this.context.identity;
@@ -350,11 +359,27 @@ class StatusActionBar extends ImmutablePureComponent {
       <IconButton className='status__action-bar__button' title={intl.formatMessage(messages.hide)} icon='eye' onClick={this.handleHideClick} />
     );
 
+    const canReact = signedIn && status.get('reactions').filter(r => r.get('count') > 0 && r.get('me')).size < maxReactions;
+    const reactButton = (
+      <IconButton
+        className='status__action-bar-button'
+        onClick={this.handleNoOp} // EmojiPickerDropdown handles that
+        title={intl.formatMessage(messages.react)}
+        disabled={!canReact}
+        icon='plus'
+      />
+    );
+
     return (
       <div className='status__action-bar'>
         <IconButton className='status__action-bar__button' title={replyTitle} icon={status.get('in_reply_to_account_id') === status.getIn(['account', 'id']) ? 'reply' : replyIcon} onClick={this.handleReplyClick} counter={status.get('replies_count')} obfuscateCount />
         <IconButton className={classNames('status__action-bar__button', { reblogPrivate })} disabled={!publicStatus && !reblogPrivate} active={status.get('reblogged')} title={reblogTitle} icon='retweet' onClick={this.handleReblogClick} counter={withCounters ? status.get('reblogs_count') : undefined} />
         <IconButton className='status__action-bar__button star-icon' animate active={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} counter={withCounters ? status.get('favourites_count') : undefined} />
+        {
+          signedIn
+            ? <EmojiPickerDropdown className='status__action-bar-button' onPickEmoji={this.handleEmojiPick} button={reactButton} disabled={!canReact} />
+            : reactButton
+        }
         <IconButton className='status__action-bar__button bookmark-icon' disabled={!signedIn} active={status.get('bookmarked')} title={intl.formatMessage(messages.bookmark)} icon='bookmark' onClick={this.handleBookmarkClick} />
 
         {shareButton}

app/javascript/mastodon/components/status_reactions.js

@@ -0,0 +1,170 @@
+import ImmutablePureComponent from 'react-immutable-pure-component';
+import PropTypes from 'prop-types';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import { autoPlayGif, reduceMotion } from '../initial_state';
+import spring from 'react-motion/lib/spring';
+import TransitionMotion from 'react-motion/lib/TransitionMotion';
+import classNames from 'classnames';
+import React from 'react';
+import unicodeMapping from '../features/emoji/emoji_unicode_mapping_light';
+import AnimatedNumber from './animated_number';
+import { assetHost } from '../utils/config';
+
+export default class StatusReactions extends ImmutablePureComponent {
+
+  static propTypes = {
+    statusId: PropTypes.string.isRequired,
+    reactions: ImmutablePropTypes.list.isRequired,
+    numVisible: PropTypes.number,
+    addReaction: PropTypes.func.isRequired,
+    canReact: PropTypes.bool.isRequired,
+    removeReaction: PropTypes.func.isRequired,
+  };
+
+  willEnter() {
+    return { scale: reduceMotion ? 1 : 0 };
+  }
+
+  willLeave() {
+    return { scale: reduceMotion ? 0 : spring(0, { stiffness: 170, damping: 26 }) };
+  }
+
+  render() {
+    const { reactions, numVisible } = this.props;
+    let visibleReactions = reactions
+      .filter(x => x.get('count') > 0)
+      .sort((a, b) => b.get('count') - a.get('count'));
+
+    if (numVisible >= 0) {
+      visibleReactions = visibleReactions.filter((_, i) => i < numVisible);
+    }
+
+    const styles = visibleReactions.map(reaction => ({
+      key: reaction.get('name'),
+      data: reaction,
+      style: { scale: reduceMotion ? 1 : spring(1, { stiffness: 150, damping: 13 }) },
+    })).toArray();
+
+    return (
+      <TransitionMotion styles={styles} willEnter={this.willEnter} willLeave={this.willLeave}>
+        {items => (
+          <div className={classNames('reactions-bar', { 'reactions-bar--empty': visibleReactions.isEmpty() })}>
+            {items.map(({ key, data, style }) => (
+              <Reaction
+                key={key}
+                statusId={this.props.statusId}
+                reaction={data}
+                style={{ transform: `scale(${style.scale})`, position: style.scale < 0.5 ? 'absolute' : 'static' }}
+                addReaction={this.props.addReaction}
+                removeReaction={this.props.removeReaction}
+                canReact={this.props.canReact}
+              />
+            ))}
+          </div>
+        )}
+      </TransitionMotion>
+    );
+  }
+
+}
+
+class Reaction extends ImmutablePureComponent {
+
+  static propTypes = {
+    statusId: PropTypes.string,
+    reaction: ImmutablePropTypes.map.isRequired,
+    addReaction: PropTypes.func.isRequired,
+    removeReaction: PropTypes.func.isRequired,
+    canReact: PropTypes.bool.isRequired,
+    style: PropTypes.object,
+  };
+
+  state = {
+    hovered: false,
+  };
+
+  handleClick = () => {
+    const { reaction, statusId, addReaction, removeReaction } = this.props;
+
+    if (reaction.get('me')) {
+      removeReaction(statusId, reaction.get('name'));
+    } else {
+      addReaction(statusId, reaction.get('name'));
+    }
+  }
+
+  handleMouseEnter = () => this.setState({ hovered: true })
+
+  handleMouseLeave = () => this.setState({ hovered: false })
+
+  render() {
+    const { reaction } = this.props;
+
+    return (
+      <button
+        className={classNames('reactions-bar__item', { active: reaction.get('me') })}
+        onClick={this.handleClick}
+        onMouseEnter={this.handleMouseEnter}
+        onMouseLeave={this.handleMouseLeave}
+        disabled={!this.props.canReact}
+        style={this.props.style}
+      >
+        <span className='reactions-bar__item__emoji'>
+          <Emoji
+            hovered={this.state.hovered}
+            emoji={reaction.get('name')}
+            url={reaction.get('url')}
+            staticUrl={reaction.get('static_url')}
+          />
+        </span>
+        <span className='reactions-bar__item__count'>
+          <AnimatedNumber value={reaction.get('count')} />
+        </span>
+      </button>
+    );
+  }
+
+}
+
+class Emoji extends React.PureComponent {
+
+  static propTypes = {
+    emoji: PropTypes.string.isRequired,
+    hovered: PropTypes.bool.isRequired,
+    url: PropTypes.string,
+    staticUrl: PropTypes.string,
+  };
+
+  render() {
+    const { emoji, hovered, url, staticUrl } = this.props;
+
+    if (unicodeMapping[emoji]) {
+      const { filename, shortCode } = unicodeMapping[this.props.emoji];
+      const title = shortCode ? `:${shortCode}:` : '';
+
+      return (
+        <img
+          draggable='false'
+          className='emojione'
+          alt={emoji}
+          title={title}
+          src={`${assetHost}/emoji/${filename}.svg`}
+        />
+      );
+    } else {
+      const filename = (autoPlayGif || hovered) ? url : staticUrl;
+      const shortCode = `:${emoji}:`;
+
+      return (
+        <img
+          draggable='false'
+          className='emojione custom-emoji'
+          alt={shortCode}
+          title={shortCode}
+          src={filename}
+        />
+      );
+    }
+  }
+
+}

app/javascript/mastodon/containers/status_container.js

@@ -1,7 +1,7 @@
 import React from 'react';
 import { connect } from 'react-redux';
 import Status from '../components/status';
-import { makeGetStatus, makeGetPictureInPicture } from '../selectors';
+import { makeGetStatus, makeGetPictureInPicture, makeCustomEmojiMap } from '../selectors';
 import {
   replyCompose,
   mentionCompose,
@@ -16,6 +16,8 @@ import {
   unbookmark,
   pin,
   unpin,
+  addReaction,
+  removeReaction,
 } from '../actions/interactions';
 import {
   muteStatus,
@@ -66,6 +68,7 @@ const makeMapStateToProps = () => {
   const mapStateToProps = (state, props) => ({
     status: getStatus(state, props),
     pictureInPicture: getPictureInPicture(state, props),
+    emojiMap: makeCustomEmojiMap(state),
   });
 
   return mapStateToProps;
@@ -129,6 +132,14 @@ const mapDispatchToProps = (dispatch, { intl, contextType }) => ({
     }
   },
 
+  onReactionAdd (statusId, name, url) {
+    dispatch(addReaction(statusId, name, url));
+  },
+
+  onReactionRemove (statusId, name) {
+    dispatch(removeReaction(statusId, name));
+  },
+
   onEmbed (status) {
     dispatch(openModal('EMBED', {
       url: status.get('url'),

app/javascript/mastodon/features/compose/components/emoji_picker_dropdown.js

@@ -319,6 +319,7 @@ class EmojiPickerDropdown extends React.PureComponent {
     onSkinTone: PropTypes.func.isRequired,
     skinTone: PropTypes.number.isRequired,
     button: PropTypes.node,
+    disabled: PropTypes.bool,
   };
 
   state = {
@@ -356,7 +357,7 @@ class EmojiPickerDropdown extends React.PureComponent {
   }
 
   onToggle = (e) => {
-    if (!this.state.loading && (!e.key || e.key === 'Enter')) {
+    if (!this.state.disabled && !this.state.loading && (!e.key || e.key === 'Enter')) {
       if (this.state.active) {
         this.onHideDropdown();
       } else {

app/javascript/mastodon/features/notifications/components/column_settings.js

@@ -115,6 +115,17 @@ export default class ColumnSettings extends React.PureComponent {
           </div>
         </div>
 
+        <div role='group' aria-labelledby='notifications-reaction'>
+          <span id='notifications-reaction' className='column-settings__section'><FormattedMessage id='notifications.column_settings.reaction' defaultMessage='Reactions:' /></span>
+
+          <div className='column-settings__pillbar'>
+            <SettingToggle disabled={browserPermission === 'denied'} prefix='notifications_desktop' settings={settings} settingPath={['alerts', 'reaction']} onChange={onChange} label={alertStr} />
+            {showPushSettings && <SettingToggle prefix='notifications_push' settings={pushSettings} settingPath={['alerts', 'reaction']} onChange={this.onPushChange} label={pushStr} />}
+            <SettingToggle prefix='notifications' settings={settings} settingPath={['shows', 'reaction']} onChange={onChange} label={showStr} />
+            <SettingToggle prefix='notifications' settings={settings} settingPath={['sounds', 'reaction']} onChange={onChange} label={soundStr} />
+          </div>
+        </div>
+
         <div role='group' aria-labelledby='notifications-mention'>
           <span id='notifications-mention' className='column-settings__section'><FormattedMessage id='notifications.column_settings.mention' defaultMessage='Mentions:' /></span>
 

app/javascript/mastodon/features/notifications/components/filter_bar.js

@@ -6,6 +6,7 @@ import Icon from 'mastodon/components/icon';
 const tooltips = defineMessages({
   mentions: { id: 'notifications.filter.mentions', defaultMessage: 'Mentions' },
   favourites: { id: 'notifications.filter.favourites', defaultMessage: 'Favourites' },
+  reactions: { id: 'notifications.filter.reactions', defaultMessage: 'Reactions' },
   boosts: { id: 'notifications.filter.boosts', defaultMessage: 'Boosts' },
   polls: { id: 'notifications.filter.polls', defaultMessage: 'Poll results' },
   follows: { id: 'notifications.filter.follows', defaultMessage: 'Follows' },
@@ -74,6 +75,13 @@ class FilterBar extends React.PureComponent {
         >
           <Icon id='star' fixedWidth />
         </button>
+        <button
+          className={selectedFilter === 'reaction' ? 'active' : ''}
+          onClick={this.onClick('reaction')}
+          title={intl.formatMessage(tooltips.reactions)}
+        >
+          <Icon id='plus' fixedWidth />
+        </button>
         <button
           className={selectedFilter === 'reblog' ? 'active' : ''}
           onClick={this.onClick('reblog')}

app/javascript/mastodon/features/notifications/components/notification.js

@@ -15,6 +15,7 @@ import classNames from 'classnames';
 
 const messages = defineMessages({
   favourite: { id: 'notification.favourite', defaultMessage: '{name} favourited your status' },
+  reaction: { id: 'notification.reaction', defaultMessage: '{name} reacted to your status' },
   follow: { id: 'notification.follow', defaultMessage: '{name} followed you' },
   ownPoll: { id: 'notification.own_poll', defaultMessage: 'Your poll has ended' },
   poll: { id: 'notification.poll', defaultMessage: 'A poll you have voted in has ended' },
@@ -213,6 +214,38 @@ class Notification extends ImmutablePureComponent {
     );
   }
 
+  renderReaction (notification, link) {
+    const { intl, unread } = this.props;
+
+    return (
+      <HotKeys handlers={this.getHandlers()}>
+        <div className={classNames('notification notification-reaction focusable', { unread })} tabIndex='0' aria-label={notificationForScreenReader(intl, intl.formatMessage(messages.reaction, { name: notification.getIn(['account', 'acct']) }), notification.get('created_at'))}>
+          <div className='notification__message'>
+            <div className='notification__favourite-icon-wrapper'>
+              <Icon id='plus' fixedWidth />
+            </div>
+
+            <span title={notification.get('created_at')}>
+              <FormattedMessage id='notification.reaction' defaultMessage='{name} reacted to your status' values={{ name: link }} />
+            </span>
+          </div>
+
+          <StatusContainer
+            id={notification.get('status')}
+            account={notification.get('account')}
+            muted
+            withDismiss
+            hidden={this.props.hidden}
+            getScrollPosition={this.props.getScrollPosition}
+            updateScrollBottom={this.props.updateScrollBottom}
+            cachedMediaWidth={this.props.cachedMediaWidth}
+            cacheMediaWidth={this.props.cacheMediaWidth}
+          />
+        </div>
+      </HotKeys>
+    );
+  }
+
   renderReblog (notification, link) {
     const { intl, unread } = this.props;
 
@@ -414,6 +447,8 @@ class Notification extends ImmutablePureComponent {
       return this.renderMention(notification);
     case 'favourite':
       return this.renderFavourite(notification, link);
+    case 'reaction':
+      return this.renderReaction(notification, link);
     case 'reblog':
       return this.renderReblog(notification, link);
     case 'status':

app/javascript/mastodon/features/status/components/action_bar.js

@@ -5,9 +5,10 @@ import IconButton from '../../../components/icon_button';
 import ImmutablePropTypes from 'react-immutable-proptypes';
 import DropdownMenuContainer from '../../../containers/dropdown_menu_container';
 import { defineMessages, injectIntl } from 'react-intl';
-import { me } from '../../../initial_state';
+import { me, maxReactions } from '../../../initial_state';
 import classNames from 'classnames';
 import { PERMISSION_MANAGE_USERS } from 'mastodon/permissions';
+import EmojiPickerDropdown from '../../compose/containers/emoji_picker_dropdown_container';
 
 const messages = defineMessages({
   delete: { id: 'status.delete', defaultMessage: 'Delete' },
@@ -21,6 +22,7 @@ const messages = defineMessages({
   cancel_reblog_private: { id: 'status.cancel_reblog_private', defaultMessage: 'Unboost' },
   cannot_reblog: { id: 'status.cannot_reblog', defaultMessage: 'This post cannot be boosted' },
   favourite: { id: 'status.favourite', defaultMessage: 'Favourite' },
+  react: { id: 'status.react', defaultMessage: 'React' },
   bookmark: { id: 'status.bookmark', defaultMessage: 'Bookmark' },
   more: { id: 'status.more', defaultMessage: 'More' },
   mute: { id: 'status.mute', defaultMessage: 'Mute @{name}' },
@@ -61,6 +63,7 @@ class ActionBar extends React.PureComponent {
     onReply: PropTypes.func.isRequired,
     onReblog: PropTypes.func.isRequired,
     onFavourite: PropTypes.func.isRequired,
+    onReactionAdd: PropTypes.func.isRequired,
     onBookmark: PropTypes.func.isRequired,
     onDelete: PropTypes.func.isRequired,
     onEdit: PropTypes.func.isRequired,
@@ -91,6 +94,10 @@ class ActionBar extends React.PureComponent {
     this.props.onFavourite(this.props.status);
   }
 
+  handleEmojiPick = data => {
+    this.props.onReactionAdd(this.props.status.get('id'), data.native.replace(/:/g, ''));
+  }
+
   handleBookmarkClick = (e) => {
     this.props.onBookmark(this.props.status, e);
   }
@@ -179,6 +186,8 @@ class ActionBar extends React.PureComponent {
     navigator.clipboard.writeText(url);
   }
 
+  handleNoOp = () => {} // hack for reaction add button
+
   render () {
     const { status, relationship, intl } = this.props;
     const { signedIn, permissions } = this.context.identity;
@@ -250,6 +259,17 @@ class ActionBar extends React.PureComponent {
       }
     }
 
+    const canReact = signedIn && status.get('reactions').filter(r => r.get('count') > 0 && r.get('me')).size < maxReactions;
+    const reactButton = (
+      <IconButton
+        className='plus-icon'
+        onClick={this.handleNoOp} // EmojiPickerDropdown handles that
+        title={intl.formatMessage(messages.react)}
+        disabled={!canReact}
+        icon='plus'
+      />
+    );
+
     const shareButton = ('share' in navigator) && publicStatus && (
       <div className='detailed-status__button'><IconButton title={intl.formatMessage(messages.share)} icon='share-alt' onClick={this.handleShare} /></div>
     );
@@ -279,6 +299,13 @@ class ActionBar extends React.PureComponent {
         <div className='detailed-status__button'><IconButton title={intl.formatMessage(messages.reply)} icon={status.get('in_reply_to_account_id') === status.getIn(['account', 'id']) ? 'reply' : replyIcon} onClick={this.handleReplyClick} /></div>
         <div className='detailed-status__button' ><IconButton className={classNames({ reblogPrivate })} disabled={!publicStatus && !reblogPrivate} active={status.get('reblogged')} title={reblogTitle} icon='retweet' onClick={this.handleReblogClick} /></div>
         <div className='detailed-status__button'><IconButton className='star-icon' animate active={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} /></div>
+        <div className='detailed-status__button'>
+          {
+            canReact
+              ? <EmojiPickerDropdown onPickEmoji={this.handleEmojiPick} button={reactButton} disabled={!canReact} />
+              : reactButton
+          }
+        </div>
         <div className='detailed-status__button'><IconButton className='bookmark-icon' disabled={!signedIn} active={status.get('bookmarked')} title={intl.formatMessage(messages.bookmark)} icon='bookmark' onClick={this.handleBookmarkClick} /></div>
 
         {shareButton}

app/javascript/mastodon/features/status/components/detailed_status.js

@@ -17,6 +17,7 @@ import Icon from 'mastodon/components/icon';
 import AnimatedNumber from 'mastodon/components/animated_number';
 import PictureInPicturePlaceholder from 'mastodon/components/picture_in_picture_placeholder';
 import EditedTimestamp from 'mastodon/components/edited_timestamp';
+import StatusReactions from 'mastodon/components/status_reactions';
 
 const messages = defineMessages({
   public_short: { id: 'privacy.public.short', defaultMessage: 'Public' },
@@ -30,6 +31,7 @@ class DetailedStatus extends ImmutablePureComponent {
 
   static contextTypes = {
     router: PropTypes.object,
+    identity: PropTypes.object,
   };
 
   static propTypes = {
@@ -48,6 +50,8 @@ class DetailedStatus extends ImmutablePureComponent {
       available: PropTypes.bool,
     }),
     onToggleMediaVisibility: PropTypes.func,
+    onReactionAdd: PropTypes.func.isRequired,
+    onReactionRemove: PropTypes.func.isRequired,
   };
 
   state = {
@@ -275,6 +279,14 @@ class DetailedStatus extends ImmutablePureComponent {
 
           {media}
 
+          <StatusReactions
+            statusId={status.get('id')}
+            reactions={status.get('reactions')}
+            addReaction={this.props.onReactionAdd}
+            removeReaction={this.props.onReactionRemove}
+            canReact={this.context.identity.signedIn}
+          />
+
           <div className='detailed-status__meta'>
             <a className='detailed-status__datetime' href={`/@${status.getIn(['account', 'acct'])}\/${status.get('id')}`} target='_blank' rel='noopener noreferrer'>
               <FormattedDate value={new Date(status.get('created_at'))} hour12={false} year='numeric' month='short' day='2-digit' hour='2-digit' minute='2-digit' />

app/javascript/mastodon/features/status/index.js

@@ -20,6 +20,8 @@ import {
   unreblog,
   pin,
   unpin,
+  addReaction,
+  removeReaction,
 } from '../../actions/interactions';
 import {
   replyCompose,
@@ -48,7 +50,7 @@ import { initMuteModal } from '../../actions/mutes';
 import { initBlockModal } from '../../actions/blocks';
 import { initBoostModal } from '../../actions/boosts';
 import { initReport } from '../../actions/reports';
-import { makeGetStatus, makeGetPictureInPicture } from '../../selectors';
+import { makeCustomEmojiMap, makeGetStatus, makeGetPictureInPicture } from '../../selectors';
 import ScrollContainer from 'mastodon/containers/scroll_container';
 import ColumnBackButton from '../../components/column_back_button';
 import ColumnHeader from '../../components/column_header';
@@ -153,6 +155,7 @@ const makeMapStateToProps = () => {
       askReplyConfirmation: state.getIn(['compose', 'text']).trim().length !== 0,
       domain: state.getIn(['meta', 'domain']),
       pictureInPicture: getPictureInPicture(state, { id: props.params.statusId }),
+      emojiMap: makeCustomEmojiMap(state),
     };
   };
 
@@ -254,6 +257,19 @@ class Status extends ImmutablePureComponent {
     }
   }
 
+  handleReactionAdd = (statusId, name, url) => {
+    const { dispatch } = this.props;
+    const { signedIn } = this.context.identity;
+
+    if (signedIn) {
+      dispatch(addReaction(statusId, name, url));
+    }
+  }
+
+  handleReactionRemove = (statusId, name) => {
+    this.props.dispatch(removeReaction(statusId, name));
+  }
+
   handlePin = (status) => {
     if (status.get('pinned')) {
       this.props.dispatch(unpin(status));
@@ -638,12 +654,15 @@ class Status extends ImmutablePureComponent {
                   status={status}
                   onOpenVideo={this.handleOpenVideo}
                   onOpenMedia={this.handleOpenMedia}
+                  onReactionAdd={this.handleReactionAdd}
+                  onReactionRemove={this.handleReactionRemove}
                   onToggleHidden={this.handleToggleHidden}
                   onTranslate={this.handleTranslate}
                   domain={domain}
                   showMedia={this.state.showMedia}
                   onToggleMediaVisibility={this.handleToggleMediaVisibility}
                   pictureInPicture={pictureInPicture}
+                  emojiMap={this.props.emojiMap}
                 />
 
                 <ActionBar
@@ -651,6 +670,7 @@ class Status extends ImmutablePureComponent {
                   status={status}
                   onReply={this.handleReplyClick}
                   onFavourite={this.handleFavouriteClick}
+                  onReactionAdd={this.handleReactionAdd}
                   onReblog={this.handleReblogClick}
                   onBookmark={this.handleBookmarkClick}
                   onDelete={this.handleDeleteClick}

app/javascript/mastodon/initial_state.js

@@ -61,6 +61,7 @@
  * @property {boolean} limited_federation_mode
  * @property {string} locale
  * @property {string | null} mascot
+ * @property {number} max_reactions
  * @property {string=} me
  * @property {string=} moved_to_account_id
  * @property {string=} owner
@@ -79,6 +80,7 @@
  * @property {boolean} use_blurhash
  * @property {boolean=} use_pending_items
  * @property {string} version
+ * @property {number} visible_reactions
  * @property {boolean} translation_enabled
  */
 
@@ -113,6 +115,7 @@ export const expandSpoilers = getMeta('expand_spoilers');
 export const forceSingleColumn = !getMeta('advanced_layout');
 export const limitedFederationMode = getMeta('limited_federation_mode');
 export const mascot = getMeta('mascot');
+export const maxReactions = (initialState && initialState.max_reactions) || 1;
 export const me = getMeta('me');
 export const movedToAccountId = getMeta('moved_to_account_id');
 export const owner = getMeta('owner');
@@ -130,6 +133,7 @@ export const unfollowModal = getMeta('unfollow_modal');
 export const useBlurhash = getMeta('use_blurhash');
 export const usePendingItems = getMeta('use_pending_items');
 export const version = getMeta('version');
+export const visibleReactions = getMeta('visible_reactions');
 export const translationEnabled = getMeta('translation_enabled');
 export const languages = initialState?.languages;
 

app/javascript/mastodon/locales/de.json

@@ -393,6 +393,7 @@
   "notification.admin.report": "{target} wurde von {name} gemeldet",
   "notification.admin.sign_up": "{name} registrierte sich",
   "notification.favourite": "{name} hat deinen Beitrag favorisiert",
+  "notification.reaction": "{name} hat auf deinen Beitrag reagiert",
   "notification.follow": "{name} folgt dir jetzt",
   "notification.follow_request": "{name} möchte dir folgen",
   "notification.mention": "{name} erwähnte dich",
@@ -407,6 +408,7 @@
   "notifications.column_settings.admin.sign_up": "Neue Registrierungen:",
   "notifications.column_settings.alert": "Desktop-Benachrichtigungen",
   "notifications.column_settings.favourite": "Favorisierungen:",
+  "notifications.column_settings.reaction": "Reaktionen:",
   "notifications.column_settings.filter_bar.advanced": "Erweiterte Filterleiste aktivieren",
   "notifications.column_settings.filter_bar.category": "Filterleiste:",
   "notifications.column_settings.filter_bar.show_bar": "Filterleiste anzeigen",
@@ -556,6 +558,7 @@
   "status.edited_x_times": "{count, plural, one {{count} mal} other {{count} mal}} bearbeitet",
   "status.embed": "Beitrag per iFrame einbetten",
   "status.favourite": "Favorisieren",
+  "status.react": "Reagieren",
   "status.filter": "Beitrag filtern",
   "status.filtered": "Gefiltert",
   "status.hide": "Beitrag verbergen",
@@ -614,6 +617,7 @@
   "timeline_hint.resources.statuses": "Ältere Beiträge",
   "trends.counter_by_accounts": "{count, plural, one {{counter} Profil} other {{counter} Profile}} {days, plural, one {seit gestern} other {in {days} Tagen}}",
   "trends.trending_now": "Aktuelle Trends",
+  "tooltips.reactions": "Reaktionen",
   "ui.beforeunload": "Dein Entwurf geht verloren, wenn du Mastodon verlässt.",
   "units.short.billion": "{count} Mrd",
   "units.short.million": "{count} Mio",

app/javascript/mastodon/locales/en.json

@@ -398,6 +398,7 @@
   "notification.admin.report": "{name} reported {target}",
   "notification.admin.sign_up": "{name} signed up",
   "notification.favourite": "{name} favourited your post",
+  "notification.reaction": "{name} reacted to your post",
   "notification.follow": "{name} followed you",
   "notification.follow_request": "{name} has requested to follow you",
   "notification.mention": "{name} mentioned you",
@@ -412,6 +413,7 @@
   "notifications.column_settings.admin.sign_up": "New sign-ups:",
   "notifications.column_settings.alert": "Desktop notifications",
   "notifications.column_settings.favourite": "Favourites:",
+  "notifications.column_settings.reaction": "Reactions:",
   "notifications.column_settings.filter_bar.advanced": "Display all categories",
   "notifications.column_settings.filter_bar.category": "Quick filter bar",
   "notifications.column_settings.filter_bar.show_bar": "Show filter bar",
@@ -561,6 +563,7 @@
   "status.edited_x_times": "Edited {count, plural, one {{count} time} other {{count} times}}",
   "status.embed": "Embed",
   "status.favourite": "Favourite",
+  "status.react": "React",
   "status.filter": "Filter this post",
   "status.filtered": "Filtered",
   "status.hide": "Hide toot",
@@ -619,6 +622,7 @@
   "timeline_hint.resources.statuses": "Older posts",
   "trends.counter_by_accounts": "{count, plural, one {{counter} person} other {{counter} people}} in the past {days, plural, one {day} other {{days} days}}",
   "trends.trending_now": "Trending now",
+  "tooltips.reactions": "Reactions",
   "ui.beforeunload": "Your draft will be lost if you leave Mastodon.",
   "units.short.billion": "{count}B",
   "units.short.million": "{count}M",

app/javascript/mastodon/reducers/settings.js

@@ -33,6 +33,7 @@ const initialState = ImmutableMap({
       follow: false,
       follow_request: false,
       favourite: false,
+      reaction: false,
       reblog: false,
       mention: false,
       poll: false,
@@ -56,6 +57,7 @@ const initialState = ImmutableMap({
       follow_request: false,
       favourite: true,
       reblog: true,
+      reaction: true,
       mention: true,
       poll: true,
       status: true,
@@ -69,6 +71,7 @@ const initialState = ImmutableMap({
       follow_request: false,
       favourite: true,
       reblog: true,
+      reaction: true,
       mention: true,
       poll: true,
       status: true,

app/javascript/mastodon/reducers/statuses.js

@@ -6,6 +6,11 @@ import {
   UNFAVOURITE_SUCCESS,
   BOOKMARK_REQUEST,
   BOOKMARK_FAIL,
+  REACTION_UPDATE,
+  REACTION_ADD_FAIL,
+  REACTION_REMOVE_FAIL,
+  REACTION_ADD_REQUEST,
+  REACTION_REMOVE_REQUEST,
 } from '../actions/interactions';
 import {
   STATUS_MUTE_SUCCESS,
@@ -35,6 +40,43 @@ const deleteStatus = (state, id, references) => {
   return state.delete(id);
 };
 
+const updateReaction = (state, id, name, updater) => state.update(
+  id,
+  status => status.update(
+    'reactions',
+    reactions => {
+      const index = reactions.findIndex(reaction => reaction.get('name') === name);
+      if (index > -1) {
+        return reactions.update(index, reaction => updater(reaction));
+      } else {
+        return reactions.push(updater(fromJS({ name, count: 0 })));
+      }
+    },
+  ),
+);
+
+const updateReactionCount = (state, reaction) => updateReaction(state, reaction.status_id, reaction.name, x => x.set('count', reaction.count));
+
+// The url parameter is only used when adding a new custom emoji reaction
+// (one that wasn't in the reactions list before) because we don't have its
+// URL yet.  In all other cases, it's undefined.
+const addReaction = (state, id, name, url) => updateReaction(
+  state,
+  id,
+  name,
+  x => x.set('me', true)
+    .update('count', n => n + 1)
+    .update('url', old => old ? old : url)
+    .update('static_url', old => old ? old : url),
+);
+
+const removeReaction = (state, id, name) => updateReaction(
+  state,
+  id,
+  name,
+  x => x.set('me', false).update('count', n => n - 1),
+);
+
 const initialState = ImmutableMap();
 
 export default function statuses(state = initialState, action) {
@@ -61,6 +103,14 @@ export default function statuses(state = initialState, action) {
     return state.setIn([action.status.get('id'), 'reblogged'], true);
   case REBLOG_FAIL:
     return state.get(action.status.get('id')) === undefined ? state : state.setIn([action.status.get('id'), 'reblogged'], false);
+  case REACTION_UPDATE:
+    return updateReactionCount(state, action.reaction);
+  case REACTION_ADD_REQUEST:
+  case REACTION_REMOVE_FAIL:
+    return addReaction(state, action.id, action.name, action.url);
+  case REACTION_REMOVE_REQUEST:
+  case REACTION_ADD_FAIL:
+    return removeReaction(state, action.id, action.name);
   case STATUS_MUTE_SUCCESS:
     return state.setIn([action.id, 'muted'], true);
   case STATUS_UNMUTE_SUCCESS:

app/javascript/mastodon/selectors/index.js

@@ -135,3 +135,11 @@ export const getAccountHidden = createSelector([
 ], (hidden, followingOrRequested, isSelf) => {
   return hidden && !(isSelf || followingOrRequested);
 });
+
+export const makeCustomEmojiMap = createSelector(
+  [state => state.get('custom_emojis')],
+  items => items.reduce(
+    (map, emoji) => map.set(emoji.get('shortcode'), emoji),
+    ImmutableMap(),
+  ),
+);

app/javascript/styles/mastodon/components.scss

@@ -1130,6 +1130,10 @@
       }
     }
   }
+
+  .reactions-bar--empty {
+    margin-top: 0;
+  }
 }
 
 .status__relative-time {
@@ -1252,6 +1256,16 @@
   align-items: center;
   gap: 18px;
   margin-top: 16px;
+
+  & > .emoji-picker-dropdown > .emoji-button {
+    padding: 0;
+  }
+}
+
+.status__action-bar-button {
+  .fa-plus {
+    padding-top: 1px;
+  }
 }
 
 .detailed-status__action-bar-dropdown {
@@ -4019,6 +4033,10 @@ a.status-card.compact:hover {
   text-align: center;
 }
 
+.detailed-status__button .emoji-button {
+  padding: 0;
+}
+
 .column-settings__outer {
   background: lighten($ui-base-color, 8%);
   padding: 15px;

app/lib/activitypub/activity.rb

@@ -39,6 +39,8 @@ class ActivityPub::Activity
         ActivityPub::Activity::Follow
       when 'Like'
         ActivityPub::Activity::Like
+      when 'EmojiReact'
+        ActivityPub::Activity::EmojiReact
       when 'Block'
         ActivityPub::Activity::Block
       when 'Update'
@@ -174,4 +176,33 @@ class ActivityPub::Activity
     Rails.logger.info("Rejected #{@json['type']} activity #{@json['id']} from #{@account.uri}#{@options[:relayed_through_actor] && "via #{@options[:relayed_through_actor].uri}"}")
     nil
   end
+
+  # Ensure all emojis declared in the activity's tags are
+  # present in the database and downloaded to the local cache.
+  # Required by EmojiReact and Like for emoji reactions.
+  def process_emoji_tags(tags)
+    as_array(tags).each do |tag|
+      process_single_emoji tag if tag['type'] == 'Emoji'
+    end
+  end
+
+  def process_single_emoji(tag)
+    custom_emoji_parser = ActivityPub::Parser::CustomEmojiParser.new(tag)
+    return if custom_emoji_parser.shortcode.blank? || custom_emoji_parser.image_remote_url.blank?
+
+    emoji = CustomEmoji.find_by(shortcode: custom_emoji_parser.shortcode, domain: @account.domain)
+    return unless emoji.nil? ||
+                  custom_emoji_parser.image_remote_url != emoji.image_remote_url ||
+                  (custom_emoji_parser.updated_at && custom_emoji_parser.updated_at >= emoji.updated_at)
+
+    begin
+      emoji ||= CustomEmoji.new(domain: @account.domain,
+                                shortcode: custom_emoji_parser.shortcode,
+                                uri: custom_emoji_parser.uri)
+      emoji.image_remote_url = custom_emoji_parser.image_remote_url
+      emoji.save
+    rescue Seahorse::Client::NetworkingError => e
+      Rails.logger.warn "Error fetching emoji: #{e}"
+    end
+  end
 end

app/lib/activitypub/activity/emoji_react.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class ActivityPub::Activity::EmojiReact < ActivityPub::Activity
+  def perform
+    original_status = status_from_uri(object_uri)
+    name = @json['content']
+    return if original_status.nil? ||
+              !original_status.account.local? ||
+              delete_arrived_first?(@json['id']) ||
+              @account.reacted?(original_status, name)
+
+    custom_emoji = nil
+    if name =~ /^:.*:$/
+      process_emoji_tags(@json['tag'])
+
+      name.delete! ':'
+      custom_emoji = CustomEmoji.find_by(shortcode: name, domain: @account.domain)
+      return if custom_emoji.nil?
+    end
+
+    reaction = original_status.status_reactions.create!(account: @account, name: name, custom_emoji: custom_emoji)
+
+    LocalNotificationWorker.perform_async(original_status.account_id, reaction.id, 'StatusReaction', 'reaction')
+  end
+end

app/lib/activitypub/activity/like.rb

@@ -3,12 +3,36 @@
 class ActivityPub::Activity::Like < ActivityPub::Activity
   def perform
     original_status = status_from_uri(object_uri)
+    return if original_status.nil? || !original_status.account.local? || delete_arrived_first?(@json['id'])
 
-    return if original_status.nil? || !original_status.account.local? || delete_arrived_first?(@json['id']) || @account.favourited?(original_status)
+    return if maybe_process_misskey_reaction(original_status)
+
+    return if @account.favourited?(original_status)
 
     favourite = original_status.favourites.create!(account: @account)
 
     LocalNotificationWorker.perform_async(original_status.account_id, favourite.id, 'Favourite', 'favourite')
     Trends.statuses.register(original_status)
   end
+
+  # Misskey delivers reactions as likes with the emoji in _misskey_reaction
+  # see https://misskey-hub.net/ns.html#misskey-reaction for details
+  def maybe_process_misskey_reaction(original_status)
+    name = @json['_misskey_reaction']
+    return false if name.nil?
+
+    custom_emoji = nil
+    if name =~ /^:.*:$/
+      process_emoji_tags(@json['tag'])
+
+      name.delete! ':'
+      custom_emoji = CustomEmoji.find_by(shortcode: name, domain: @account.domain)
+      return false if custom_emoji.nil? # invalid custom emoji, treat it as a regular like
+    end
+    return true if @account.reacted?(original_status, name)
+
+    reaction = original_status.status_reactions.create!(account: @account, name: name, custom_emoji: custom_emoji)
+    LocalNotificationWorker.perform_async(original_status.account_id, reaction.id, 'StatusReaction', 'reaction')
+    true
+  end
 end

app/lib/activitypub/activity/undo.rb

@@ -11,6 +11,8 @@ class ActivityPub::Activity::Undo < ActivityPub::Activity
       undo_follow
     when 'Like'
       undo_like
+    when 'EmojiReact'
+      undo_emoji_react
     when 'Block'
       undo_block
     when nil
@@ -113,6 +115,22 @@ class ActivityPub::Activity::Undo < ActivityPub::Activity
     end
   end
 
+  def undo_emoji_react
+    name = @object['content']
+    return if name.nil?
+
+    status = status_from_uri(target_uri)
+
+    return if status.nil? || !status.account.local?
+
+    if @account.reacted?(status, name.delete(':'))
+      reaction = status.status_reactions.where(account: @account, name: name).first
+      reaction&.destroy
+    else
+      delete_later!(object_uri)
+    end
+  end
+
   def undo_block
     target_account = account_from_uri(target_uri)
 

app/lib/user_settings_decorator.rb

@@ -43,6 +43,7 @@ class UserSettingsDecorator
     user.settings['use_pending_items']   = use_pending_items_preference if change?('setting_use_pending_items')
     user.settings['trends']              = trends_preference if change?('setting_trends')
     user.settings['crop_images']         = crop_images_preference if change?('setting_crop_images')
+    user.settings['visible_reactions']   = visible_reactions_preference if change?('setting_visible_reactions')
     user.settings['always_send_emails']  = always_send_emails_preference if change?('setting_always_send_emails')
   end
 
@@ -158,6 +159,10 @@ class UserSettingsDecorator
     boolean_cast_setting 'setting_crop_images'
   end
 
+  def visible_reactions_preference
+    integer_cast_setting('setting_visible_reactions', 0)
+  end
+
   def always_send_emails_preference
     boolean_cast_setting 'setting_always_send_emails'
   end
@@ -166,6 +171,15 @@ class UserSettingsDecorator
     ActiveModel::Type::Boolean.new.cast(settings[key])
   end
 
+  def integer_cast_setting(key, min = nil, max = nil)
+    i = ActiveModel::Type::Integer.new.cast(settings[key])
+    # the cast above doesn't return a number if passed the string "e"
+    i = 0 unless i.is_a? Numeric
+    return min if !min.nil? && i < min
+    return max if !max.nil? && i > max
+    i
+  end
+
   def coerced_settings(key)
     coerce_values settings.fetch(key, {})
   end

app/models/concerns/account_interactions.rb

@@ -239,6 +239,10 @@ module AccountInteractions
     status.proper.favourites.where(account: self).exists?
   end
 
+  def reacted?(status, name)
+    status.proper.status_reactions.where(account: self, name: name).exists?
+  end
+
   def bookmarked?(status)
     status.proper.bookmarks.where(account: self).exists?
   end

app/models/notification.rb

@@ -24,6 +24,7 @@ class Notification < ApplicationRecord
     'Follow'         => :follow,
     'FollowRequest'  => :follow_request,
     'Favourite'      => :favourite,
+    'StatusReaction' => :reaction,
     'Poll'           => :poll,
   }.freeze
 
@@ -34,6 +35,7 @@ class Notification < ApplicationRecord
     follow
     follow_request
     favourite
+    reaction
     poll
     update
     admin.sign_up
@@ -45,6 +47,7 @@ class Notification < ApplicationRecord
     reblog: [status: :reblog],
     mention: [mention: :status],
     favourite: [favourite: :status],
+    reaction: [status_reaction: :status],
     poll: [poll: :status],
     update: :status,
     'admin.report': [report: :target_account],
@@ -61,6 +64,7 @@ class Notification < ApplicationRecord
   belongs_to :favourite,       foreign_key: 'activity_id', optional: true
   belongs_to :poll,            foreign_key: 'activity_id', optional: true
   belongs_to :report,          foreign_key: 'activity_id', optional: true
+  belongs_to :status_reaction, foreign_key: 'activity_id', optional: true
 
   validates :type, inclusion: { in: TYPES }
 
@@ -78,6 +82,8 @@ class Notification < ApplicationRecord
       status&.reblog
     when :favourite
       favourite&.status
+    when :reaction
+      status_reaction&.status
     when :mention
       mention&.status
     when :poll
@@ -129,6 +135,8 @@ class Notification < ApplicationRecord
           notification.status.reblog = cached_status
         when :favourite
           notification.favourite.status = cached_status
+        when :reaction
+          notification.reaction.status = cached_status
         when :mention
           notification.mention.status = cached_status
         when :poll
@@ -140,6 +148,8 @@ class Notification < ApplicationRecord
     end
   end
 
+  alias reaction status_reaction
+
   after_initialize :set_from_account
   before_validation :set_from_account
 
@@ -149,7 +159,7 @@ class Notification < ApplicationRecord
     return unless new_record?
 
     case activity_type
-    when 'Status', 'Follow', 'Favourite', 'FollowRequest', 'Poll', 'Report'
+    when 'Status', 'Follow', 'Favourite', 'StatusReaction', 'FollowRequest', 'Poll', 'Report'
       self.from_account_id = activity&.account_id
     when 'Mention'
       self.from_account_id = activity&.status&.account_id

app/models/status.rb

@@ -74,6 +74,7 @@ class Status < ApplicationRecord
   has_many :active_mentions, -> { active }, class_name: 'Mention', inverse_of: :status
   has_many :media_attachments, dependent: :nullify
   has_many :quoted, foreign_key: 'quote_id', class_name: 'Status', inverse_of: :quote, dependent: :nullify
+  has_many :status_reactions, inverse_of: :status, dependent: :destroy
 
   has_and_belongs_to_many :tags
   has_and_belongs_to_many :preview_cards
@@ -287,6 +288,21 @@ class Status < ApplicationRecord
     @emojis = CustomEmoji.from_text(fields.join(' '), account.domain) + (quote? ? CustomEmoji.from_text([quote.spoiler_text, quote.text].join(' '), quote.account.domain) : [])
   end
 
+  def reactions(account = nil)
+    records = begin
+      scope = status_reactions.group(:status_id, :name, :custom_emoji_id).order(Arel.sql('MIN(created_at) ASC'))
+
+      if account.nil?
+        scope.select('name, custom_emoji_id, count(*) as count, false as me')
+      else
+        scope.select("name, custom_emoji_id, count(*) as count, exists(select 1 from status_reactions r where r.account_id = #{account.id} and r.status_id = status_reactions.status_id and r.name = status_reactions.name) as me")
+      end
+    end
+
+    ActiveRecord::Associations::Preloader.new.preload(records, :custom_emoji)
+    records
+  end
+
   def ordered_media_attachments
     if ordered_media_attachment_ids.nil?
       media_attachments

app/models/status_reaction.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+# == Schema Information
+#
+# Table name: status_reactions
+#
+#  id              :bigint(8)        not null, primary key
+#  account_id      :bigint(8)        not null
+#  status_id       :bigint(8)        not null
+#  name            :string           default(""), not null
+#  custom_emoji_id :bigint(8)
+#  created_at      :datetime         not null
+#  updated_at      :datetime         not null
+#
+class StatusReaction < ApplicationRecord
+  belongs_to :account
+  belongs_to :status, inverse_of: :status_reactions
+  belongs_to :custom_emoji, optional: true
+
+  has_one :notification, as: :activity, dependent: :destroy
+
+  validates :name, presence: true
+  validates_with StatusReactionValidator
+
+  before_validation :set_custom_emoji
+
+  private
+
+  def set_custom_emoji
+    self.custom_emoji = CustomEmoji.find_by(shortcode: name, domain: account.domain) if name.blank?
+  end
+end

app/models/user.rb

@@ -134,7 +134,7 @@ class User < ApplicationRecord
   delegate :auto_play_gif, :default_sensitive, :unfollow_modal, :boost_modal, :favourite_modal, :delete_modal,
            :reduce_motion, :system_font_ui, :noindex, :flavour, :skin, :display_media, :hide_followers_count,
            :expand_spoilers, :default_language, :aggregate_reblogs, :show_application,
-           :advanced_layout, :use_blurhash, :use_pending_items, :trends, :crop_images,
+           :advanced_layout, :use_blurhash, :use_pending_items, :trends, :crop_images, :visible_reactions,
            :disable_swiping, :always_send_emails, :default_content_type, :system_emoji_font,
            to: :settings, prefix: :setting, allow_nil: false
 

app/serializers/activitypub/emoji_reaction_serializer.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class ActivityPub::EmojiReactionSerializer < ActivityPub::Serializer
+  attributes :id, :type, :actor, :content
+  attribute :virtual_object, key: :object
+  attribute :custom_emoji, key: :tag, unless: -> { object.custom_emoji.nil? }
+
+  def id
+    [ActivityPub::TagManager.instance.uri_for(object.account), '#emoji_reactions/', object.id].join
+  end
+
+  def type
+    'EmojiReact'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def virtual_object
+    ActivityPub::TagManager.instance.uri_for(object.status)
+  end
+
+  def content
+    if object.custom_emoji.nil?
+      object.name
+    else
+      ":#{object.name}:"
+    end
+  end
+
+  alias reaction content
+
+  # Akkoma (and possibly others) expect `tag` to be an array, so we can't just
+  # use the has_one shorthand because we need to wrap it into an array manually
+  def custom_emoji
+    [ActivityPub::EmojiSerializer.new(object.custom_emoji).serializable_hash]
+  end
+end

app/serializers/activitypub/undo_emoji_reaction_serializer.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class ActivityPub::UndoEmojiReactionSerializer < ActivityPub::Serializer
+  attributes :id, :type, :actor
+
+  has_one :object, serializer: ActivityPub::EmojiReactionSerializer
+
+  def id
+    [ActivityPub::TagManager.instance.uri_for(object.account), '#emoji_reactions/', object.id, '/undo'].join
+  end
+
+  def type
+    'Undo'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+end

app/serializers/initial_state_serializer.rb

@@ -6,7 +6,7 @@ class InitialStateSerializer < ActiveModel::Serializer
   attributes :meta, :compose, :accounts,
              :media_attachments, :settings,
              :max_toot_chars, :poll_limits,
-             :languages
+             :languages, :max_reactions
 
   has_one :push_subscription, serializer: REST::WebPushSubscriptionSerializer
   has_one :role, serializer: REST::RoleSerializer
@@ -15,6 +15,10 @@ class InitialStateSerializer < ActiveModel::Serializer
     StatusLengthValidator::MAX_CHARS
   end
 
+  def max_reactions
+    StatusReactionValidator::LIMIT
+  end
+
   def poll_limits
     {
       max_options: PollValidator::MAX_OPTIONS,
@@ -66,6 +70,7 @@ class InitialStateSerializer < ActiveModel::Serializer
       store[:default_content_type] = object.current_account.user.setting_default_content_type
       store[:system_emoji_font] = object.current_account.user.setting_system_emoji_font
       store[:crop_images]       = object.current_account.user.setting_crop_images
+      store[:visible_reactions] = object.current_account.user.setting_visible_reactions
     else
       store[:auto_play_gif] = Setting.auto_play_gif
       store[:display_media] = Setting.display_media

app/serializers/rest/instance_serializer.rb

@@ -76,6 +76,10 @@ class REST::InstanceSerializer < ActiveModel::Serializer
       translation: {
         enabled: TranslationService.configured?,
       },
+
+      reactions: {
+        max_reactions: StatusReactionValidator::LIMIT,
+      },
     }
   end
 

app/serializers/rest/notification_serializer.rb

@@ -12,7 +12,7 @@ class REST::NotificationSerializer < ActiveModel::Serializer
   end
 
   def status_type?
-    [:favourite, :reblog, :status, :mention, :poll, :update].include?(object.type)
+    [:favourite, :reaction, :reblog, :status, :mention, :poll, :update].include?(object.type)
   end
 
   def report_type?

app/serializers/rest/reaction_serializer.rb

@@ -21,6 +21,14 @@ class REST::ReactionSerializer < ActiveModel::Serializer
     object.custom_emoji.present?
   end
 
+  def name
+    if extern?
+      [object.name, '@', object.custom_emoji.domain].join
+    else
+      object.name
+    end
+  end
+
   def url
     full_asset_url(object.custom_emoji.image.url)
   end
@@ -28,4 +36,10 @@ class REST::ReactionSerializer < ActiveModel::Serializer
   def static_url
     full_asset_url(object.custom_emoji.image.url(:static))
   end
+
+  private
+
+  def extern?
+    custom_emoji? && object.custom_emoji.domain.present?
+  end
 end

app/serializers/rest/status_serializer.rb

@@ -28,6 +28,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   has_many :ordered_mentions, key: :mentions
   has_many :tags
   has_many :emojis, serializer: REST::CustomEmojiSerializer
+  has_many :reactions, serializer: REST::ReactionSerializer
 
   has_one :preview_card, key: :card, serializer: REST::PreviewCardSerializer
   has_one :preloadable_poll, key: :poll, serializer: REST::PollSerializer
@@ -146,6 +147,10 @@ class REST::StatusSerializer < ActiveModel::Serializer
     object.active_mentions.to_a.sort_by(&:id)
   end
 
+  def reactions
+    object.reactions(current_user&.account)
+  end
+
   class ApplicationSerializer < ActiveModel::Serializer
     attributes :name, :website
 

app/serializers/rest/v1/instance_serializer.rb

@@ -96,6 +96,10 @@ class REST::V1::InstanceSerializer < ActiveModel::Serializer
         min_expiration: PollValidator::MIN_EXPIRATION,
         max_expiration: PollValidator::MAX_EXPIRATION,
       },
+
+      reactions: {
+        max_reactions: StatusReactionValidator::LIMIT,
+      },
     }
   end
 

app/services/react_service.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class ReactService < BaseService
+  include Authorization
+  include Payloadable
+
+  def call(account, status, emoji)
+    name, domain = emoji.split('@')
+    custom_emoji = CustomEmoji.find_by(shortcode: name, domain: domain)
+    reaction = StatusReaction.find_by(account: account, status: status, name: name, custom_emoji: custom_emoji)
+    return reaction unless reaction.nil?
+
+    reaction = StatusReaction.create!(account: account, status: status, name: name, custom_emoji: custom_emoji)
+
+    json = Oj.dump(serialize_payload(reaction, ActivityPub::EmojiReactionSerializer))
+    if status.account.local?
+      NotifyService.new.call(status.account, :reaction, reaction)
+      ActivityPub::RawDistributionWorker.perform_async(json, status.account.id)
+    else
+      ActivityPub::DeliveryWorker.perform_async(json, reaction.account_id, status.account.inbox_url)
+    end
+
+    ActivityTracker.increment('activity:interactions')
+
+    reaction
+  end
+end

app/services/unreact_service.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class UnreactService < BaseService
+  include Payloadable
+
+  def call(account, status, name)
+    reaction = StatusReaction.find_by(account: account, status: status, name: name)
+    return if reaction.nil?
+
+    reaction.destroy!
+
+    json = Oj.dump(serialize_payload(reaction, ActivityPub::UndoEmojiReactionSerializer))
+    if status.account.local?
+      ActivityPub::RawDistributionWorker.perform_async(json, status.account.id)
+    else
+      ActivityPub::DeliveryWorker.perform_async(json, reaction.account_id, status.account.inbox_url)
+    end
+
+    reaction
+  end
+end

app/validators/status_reaction_validator.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class StatusReactionValidator < ActiveModel::Validator
+  SUPPORTED_EMOJIS = Oj.load_file(Rails.root.join('app', 'javascript', 'mastodon', 'features', 'emoji', 'emoji_map.json').to_s).keys.freeze
+
+  LIMIT = [1, (ENV['MAX_REACTIONS'] || 1).to_i].max
+
+  def validate(reaction)
+    return if reaction.name.blank?
+
+    reaction.errors.add(:name, I18n.t('reactions.errors.unrecognized_emoji')) if reaction.custom_emoji_id.blank? && !unicode_emoji?(reaction.name)
+    reaction.errors.add(:base, I18n.t('reactions.errors.limit_reached')) if reaction.account.local? && limit_reached?(reaction)
+  end
+
+  private
+
+  def unicode_emoji?(name)
+    SUPPORTED_EMOJIS.include?(name)
+  end
+
+  def limit_reached?(reaction)
+    reaction.status.status_reactions.where(status: reaction.status, account: reaction.account).count >= LIMIT
+  end
+end

app/views/settings/preferences/appearance/show.html.haml

@@ -38,6 +38,9 @@
   .fields-group
     = f.input :setting_crop_images, as: :boolean, wrapper: :with_label
 
+  .fields-group.fields-row__column.fields-row__column-6
+    = f.input :setting_visible_reactions, wrapper: :with_label, input_html: { type: 'number', min: '0', data: { default: '6' } }, hint: false
+
   %h4= t 'appearance.discovery'
 
   .fields-group

config/locales-glitch/de.yml

@@ -38,5 +38,10 @@ de:
       title: Benutzer-Verifizierung
   generic:
     use_this: Benutze das
+  notification_mailer:
+    reaction:
+      body: "%{name} hat auf deinen Beitrag reagiert:"
+      subject: "%{name} hat auf deinen Beitrag reagiert"
+      title: Neue Reaktion
   settings:
     flavours: Varianten

config/locales-glitch/en.yml

@@ -38,5 +38,10 @@ en:
       title: User verification
   generic:
     use_this: Use this
+  notification_mailer:
+    reaction:
+      body: "%{name} reacted to your post:"
+      subject: "%{name} reacted to your post"
+      title: New reaction
   settings:
     flavours: Flavours

config/locales-glitch/fr.yml

@@ -38,5 +38,10 @@ fr:
       title: Vérification de l'utilisateur
   generic:
     use_this: Utiliser ceci
+  notification_mailer:
+    reaction:
+      body: "%{name} a réagi·e à votre message:"
+      subject: "%{name} a réagi·e à votre message"
+      title: Nouvelle réaction
   settings:
     flavours: Thèmes

config/locales-glitch/simple_form.de.yml

@@ -21,6 +21,7 @@ de:
         setting_hide_followers_count: Anzahl der Follower verbergen
         setting_skin: Skin
         setting_system_emoji_font: Systemschriftart für Emojis verwenden (nur für Glitch-Variante)
+        setting_visible_reactions: Anzahl der sichtbaren Emoji-Reaktionen
       notification_emails:
         trending_link: Neuer angesagter Link muss überprüft werden
         trending_status: Neuer angesagter Post muss überprüft werden

config/locales-glitch/simple_form.en.yml

@@ -21,6 +21,7 @@ en:
         setting_hide_followers_count: Hide your followers count
         setting_skin: Skin
         setting_system_emoji_font: Use system's default font for emojis (applies to Glitch flavour only)
+        setting_visible_reactions: Number of visible emoji reactions
       notification_emails:
         trending_link: New trending link requires review
         trending_status: New trending post requires review

config/locales-glitch/simple_form.fr.yml

@@ -21,6 +21,7 @@ fr:
         setting_hide_followers_count: Cacher votre nombre d'abonné·e·s
         setting_skin: Thème
         setting_system_emoji_font: Utiliser la police par défaut du système pour les émojis (s'applique uniquement au mode Glitch)
+        setting_visible_reactions: Nombre de réactions emoji visibles
       notification_emails:
         trending_link: Un nouveau lien en tendances nécessite un examen
         trending_status: Un nouveau post en tendances nécessite un examen

config/locales/en_GB.yml

@@ -721,6 +721,10 @@ en_GB:
       body: 'You were mentioned by %{name} in:'
       subject: You were mentioned by %{name}
       title: New mention
+    reaction:
+      body: "%{name} reacted on your post with %{reaction}:"
+      subject: "%{name} reacted on your post"
+      title: New reaction
     reblog:
       body: 'Your status was boosted by %{name}:'
       subject: "%{name} boosted your status"

config/routes.rb

@@ -442,6 +442,11 @@ Rails.application.routes.draw do
           resource :favourite, only: :create
           post :unfavourite, to: 'favourites#destroy'
 
+          # foreign custom emojis are encoded as shortcode@domain.tld
+          # the constraint prevents rails from interpreting the ".tld" as a filename extension
+          post '/react/:id', to: 'reactions#create', constraints: { id: /[^\/]+/ }
+          post '/unreact/:id', to: 'reactions#destroy', constraints: { id: /[^\/]+/ }
+
           resource :bookmark, only: :create
           post :unbookmark, to: 'bookmarks#destroy'
 

config/settings.yml

@@ -42,6 +42,7 @@ defaults: &defaults
   trendable_by_default: false
   trending_status_cw: true
   crop_images: true
+  visible_reactions: 6
   notification_emails:
     follow: true
     reblog: false

db/migrate/20221124114030_create_status_reactions.rb

@@ -0,0 +1,14 @@
+class CreateStatusReactions < ActiveRecord::Migration[6.1]
+  def change
+    create_table :status_reactions do |t|
+      t.references :account, null: false, foreign_key: { on_delete: :cascade }
+      t.references :status, null: false, foreign_key: { on_delete: :cascade }
+      t.string :name, null: false, default: ''
+      t.references :custom_emoji, null: true, foreign_key: { on_delete: :cascade }
+
+      t.timestamps
+    end
+
+    add_index :status_reactions, [:account_id, :status_id, :name], unique: true, name: :index_status_reactions_on_account_id_and_status_id
+  end
+end

db/schema.rb

@@ -897,6 +897,19 @@ ActiveRecord::Schema.define(version: 2022_12_06_114142) do
     t.index ["status_id"], name: "index_status_pins_on_status_id"
   end
 
+  create_table "status_reactions", force: :cascade do |t|
+    t.bigint "account_id", null: false
+    t.bigint "status_id", null: false
+    t.string "name", default: "", null: false
+    t.bigint "custom_emoji_id"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["account_id", "status_id", "name"], name: "index_status_reactions_on_account_id_and_status_id", unique: true
+    t.index ["account_id"], name: "index_status_reactions_on_account_id"
+    t.index ["custom_emoji_id"], name: "index_status_reactions_on_custom_emoji_id"
+    t.index ["status_id"], name: "index_status_reactions_on_status_id"
+  end
+
   create_table "status_stats", force: :cascade do |t|
     t.bigint "status_id", null: false
     t.bigint "replies_count", default: 0, null: false
@@ -1213,6 +1226,9 @@ ActiveRecord::Schema.define(version: 2022_12_06_114142) do
   add_foreign_key "status_edits", "statuses", on_delete: :cascade
   add_foreign_key "status_pins", "accounts", name: "fk_d4cb435b62", on_delete: :cascade
   add_foreign_key "status_pins", "statuses", on_delete: :cascade
+  add_foreign_key "status_reactions", "accounts", on_delete: :cascade
+  add_foreign_key "status_reactions", "custom_emojis", on_delete: :cascade
+  add_foreign_key "status_reactions", "statuses", on_delete: :cascade
   add_foreign_key "status_stats", "statuses", on_delete: :cascade
   add_foreign_key "status_trends", "accounts", on_delete: :cascade
   add_foreign_key "status_trends", "statuses", on_delete: :cascade

spec/fabricators/status_reaction_fabricator.rb

@@ -0,0 +1,6 @@
+Fabricator(:status_reaction) do
+  account      nil
+  status       nil
+  name         "MyString"
+  custom_emoji nil
+end

spec/models/status_reaction_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe StatusReaction, type: :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end