diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -277,7 +277,7 @@
   endsCluster: boolean,
   +robotext: EntityText,
   +threadCreatedFromMessage: ?ThreadInfo,
-  +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions: ReactionInfo,
 };
 export type ChatMessageInfoItem =
   | RobotextChatMessageInfoItem
@@ -290,10 +290,12 @@
       +startsCluster: boolean,
       endsCluster: boolean,
       +threadCreatedFromMessage: ?ThreadInfo,
-      +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+      +reactions: ReactionInfo,
     };
 export type ChatMessageItem = { itemType: 'loader' } | ChatMessageInfoItem;
-export type MessageReactionInfo = {
+
+export type ReactionInfo = { +[reaction: string]: MessageReactionInfo };
+type MessageReactionInfo = {
   +viewerReacted: boolean,
   +users: $ReadOnlyArray<RelativeUserInfo>,
 };
@@ -408,41 +410,40 @@
         ? threadInfoFromSourceMessageID[messageInfo.id]
         : undefined;
 
-    const renderedReactions: $ReadOnlyMap<string, MessageReactionInfo> =
-      (() => {
-        const result = new Map<string, MessageReactionInfo>();
+    const renderedReactions: ReactionInfo = (() => {
+      const result = {};
 
-        let messageReactsMap;
-        if (originalMessageInfo.id) {
-          messageReactsMap = targetMessageReactionsMap.get(
-            originalMessageInfo.id,
-          );
-        }
+      let messageReactsMap;
+      if (originalMessageInfo.id) {
+        messageReactsMap = targetMessageReactionsMap.get(
+          originalMessageInfo.id,
+        );
+      }
 
-        if (!messageReactsMap) {
-          return result;
-        }
+      if (!messageReactsMap) {
+        return result;
+      }
 
-        for (const reaction of messageReactsMap.keys()) {
-          const reactionUsersInfoMap = messageReactsMap.get(reaction);
-          invariant(reactionUsersInfoMap, 'reactionUsersInfoMap should be set');
+      for (const reaction of messageReactsMap.keys()) {
+        const reactionUsersInfoMap = messageReactsMap.get(reaction);
+        invariant(reactionUsersInfoMap, 'reactionUsersInfoMap should be set');
 
-          if (reactionUsersInfoMap.size === 0) {
-            continue;
-          }
+        if (reactionUsersInfoMap.size === 0) {
+          continue;
+        }
 
-          const reactionUserInfos = [...reactionUsersInfoMap.values()];
+        const reactionUserInfos = [...reactionUsersInfoMap.values()];
 
-          const messageReactionInfo = {
-            users: reactionUserInfos,
-            viewerReacted: reactionUsersInfoMap.has(viewerID),
-          };
+        const messageReactionInfo = {
+          users: reactionUserInfos,
+          viewerReacted: reactionUsersInfoMap.has(viewerID),
+        };
 
-          result.set(reaction, messageReactionInfo);
-        }
+        result[reaction] = messageReactionInfo;
+      }
 
-        return result;
-      })();
+      return result;
+    })();
 
     if (isComposableMessageType(originalMessageInfo.type)) {
       // We use these invariants instead of just checking the messageInfo.type
diff --git a/lib/shared/reaction-utils.js b/lib/shared/reaction-utils.js
--- a/lib/shared/reaction-utils.js
+++ b/lib/shared/reaction-utils.js
@@ -1,6 +1,5 @@
 // @flow
 
-import invariant from 'invariant';
 import _sortBy from 'lodash/fp/sortBy.js';
 import * as React from 'react';
 
@@ -8,7 +7,7 @@
 import { threadHasPermission } from './thread-utils.js';
 import { stringForUserExplicit } from './user-utils.js';
 import { useENSNames } from '../hooks/ens-cache.js';
-import type { MessageReactionInfo } from '../selectors/chat-selectors.js';
+import type { ReactionInfo } from '../selectors/chat-selectors.js';
 import type {
   RobotextMessageInfo,
   ComposableMessageInfo,
@@ -16,14 +15,11 @@
 import { threadPermissions, type ThreadInfo } from '../types/thread-types.js';
 import { useSelector } from '../utils/redux-utils.js';
 
-function stringForReactionList(
-  reactions: $ReadOnlyMap<string, MessageReactionInfo>,
-): string {
+function stringForReactionList(reactions: ReactionInfo): string {
   const reactionText = [];
 
-  for (const reaction of reactions.keys()) {
-    const reactionInfo = reactions.get(reaction);
-    invariant(reactionInfo, 'reactionInfo should be set');
+  for (const reaction in reactions) {
+    const reactionInfo = reactions[reaction];
 
     reactionText.push(reaction);
     const { length: numberOfReacts } = reactionInfo.users;
@@ -44,12 +40,14 @@
 };
 
 function useMessageReactionsList(
-  reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  reactions: ReactionInfo,
 ): $ReadOnlyArray<MessageReactionListInfo> {
   const withoutENSNames = React.useMemo(() => {
     const result = [];
 
-    for (const [reaction, reactionInfo] of reactions) {
+    for (const reaction in reactions) {
+      const reactionInfo = reactions[reaction];
+
       reactionInfo.users.forEach(user => {
         result.push({
           ...user,
@@ -60,7 +58,7 @@
     }
 
     const sortByNumReactions = (reactionInfo: MessageReactionListInfo) => {
-      const numOfReactions = reactions.get(reactionInfo.reaction)?.users.length;
+      const numOfReactions = reactions[reactionInfo.reaction].users.length;
       return numOfReactions ? -numOfReactions : 0;
     };
 
diff --git a/lib/shared/reaction-utils.test.js b/lib/shared/reaction-utils.test.js
--- a/lib/shared/reaction-utils.test.js
+++ b/lib/shared/reaction-utils.test.js
@@ -1,156 +1,158 @@
 // @flow
 
 import { stringForReactionList } from './reaction-utils.js';
-import type { MessageReactionInfo } from '../selectors/chat-selectors.js';
-
-describe(
-  'stringForReactionList(' +
-    'reactions: $ReadOnlyMap<string, MessageReactionInfo>)',
-  () => {
-    it(
-      'should return (👍 3) for a message with three user likes' +
-        ' including the viewer',
-      () => {
-        const messageLikesUsers = [
-          { id: '83810', isViewer: true, username: 'ginsu' },
-          { id: '86622', isViewer: false, username: 'ashoat' },
-          { id: '83889', isViewer: false, username: 'atul' },
-        ];
-        const messageLikesInfo = {
-          users: messageLikesUsers,
-          viewerReacted: true,
-        };
-
-        const reactionsMap = new Map<string, MessageReactionInfo>();
-        reactionsMap.set('👍', messageLikesInfo);
-
-        expect(stringForReactionList(reactionsMap)).toBe('👍 3');
-      },
-    );
-
-    it(
-      'should return (👍 3) for a message with three user likes' +
-        ' not including the viewer',
-      () => {
-        const messageLikesUsers = [
-          { id: '83810', isViewer: false, username: 'ginsu' },
-          { id: '86622', isViewer: false, username: 'ashoat' },
-          { id: '83889', isViewer: false, username: 'atul' },
-        ];
-        const messageLikesInfo = {
-          users: messageLikesUsers,
-          viewerReacted: false,
-        };
-
-        const reactionsMap = new Map<string, MessageReactionInfo>();
-        reactionsMap.set('👍', messageLikesInfo);
-
-        expect(stringForReactionList(reactionsMap)).toBe('👍 3');
-      },
-    );
-
-    it(
-      'should return (👍) for a message with one user like' +
-        ' including the viewer',
-      () => {
-        const messageLikesUsers = [
-          { id: '83810', isViewer: false, username: 'ginsu' },
-        ];
-        const messageLikesInfo = {
-          users: messageLikesUsers,
-          viewerReacted: true,
-        };
-
-        const reactionsMap = new Map<string, MessageReactionInfo>();
-        reactionsMap.set('👍', messageLikesInfo);
-
-        expect(stringForReactionList(reactionsMap)).toBe('👍');
-      },
-    );
-
-    it(
-      'should return (👍) for a message with one user like' +
-        ' not including the viewer',
-      () => {
-        const messageLikesUsers = [
-          { id: '83810', isViewer: false, username: 'ashoat' },
-        ];
-        const messageLikesInfo = {
-          users: messageLikesUsers,
-          viewerReacted: false,
-        };
-
-        const reactionsMap = new Map<string, MessageReactionInfo>();
-        reactionsMap.set('👍', messageLikesInfo);
-
-        expect(stringForReactionList(reactionsMap)).toBe('👍');
-      },
-    );
-
-    it('should return an empty string for a message no reactions', () => {
-      const reactionsMap = new Map<string, MessageReactionInfo>();
-
-      expect(stringForReactionList(reactionsMap)).toBe('');
-    });
-
-    it(
-      'should return (👍 😆 3) for a message with one like not including' +
-        ' the viewer and three laugh reactions including the viewer',
-      () => {
-        const messageLikesUsers = [
-          { id: '83810', isViewer: false, username: 'varun' },
-        ];
-        const messageLikesInfo = {
-          users: messageLikesUsers,
-          viewerReacted: false,
-        };
-
-        const messageLaughsUsers = [
-          { id: '12345', isViewer: true, username: 'ginsu' },
-          { id: '67890', isViewer: false, username: 'ashoat' },
-          { id: '83889', isViewer: false, username: 'atul' },
-        ];
-        const messageLaughsInfo = {
-          users: messageLaughsUsers,
-          viewerReacted: true,
-        };
-
-        const reactionsMap = new Map<string, MessageReactionInfo>();
-        reactionsMap.set('👍', messageLikesInfo);
-        reactionsMap.set('😆', messageLaughsInfo);
-
-        expect(stringForReactionList(reactionsMap)).toBe('👍 😆 3');
-      },
-    );
-
-    it(
-      'should return (👍 9+) for a message with 12 user likes' +
-        ' not including the viewer',
-      () => {
-        const messageLikesUsers = [
-          { id: '86622', isViewer: false, username: 'ginsu' },
-          { id: '12345', isViewer: false, username: 'ashoat' },
-          { id: '67890', isViewer: false, username: 'atul' },
-          { id: '83889', isViewer: false, username: 'varun' },
-          { id: '49203', isViewer: false, username: 'tomek' },
-          { id: '83029', isViewer: false, username: 'max' },
-          { id: '72902', isViewer: false, username: 'jon' },
-          { id: '49022', isViewer: false, username: 'mark' },
-          { id: '48902', isViewer: false, username: 'kamil' },
-          { id: '80922', isViewer: false, username: 'marcin' },
-          { id: '12890', isViewer: false, username: 'inka' },
-          { id: '67891', isViewer: false, username: 'przemek' },
-        ];
-        const messageLikesInfo = {
-          users: messageLikesUsers,
-          viewerReacted: false,
-        };
-
-        const reactionsMap = new Map<string, MessageReactionInfo>();
-        reactionsMap.set('👍', messageLikesInfo);
-
-        expect(stringForReactionList(reactionsMap)).toBe('👍 9+');
-      },
-    );
-  },
-);
+import type { ReactionInfo } from '../selectors/chat-selectors.js';
+
+describe('stringForReactionList(reactions: ReactionInfo)', () => {
+  it(
+    'should return (👍 3) for a message with three user likes' +
+      ' including the viewer',
+    () => {
+      const messageLikesUsers = [
+        { id: '83810', isViewer: true, username: 'ginsu' },
+        { id: '86622', isViewer: false, username: 'ashoat' },
+        { id: '83889', isViewer: false, username: 'atul' },
+      ];
+      const messageLikesInfo = {
+        users: messageLikesUsers,
+        viewerReacted: true,
+      };
+
+      const reactions: ReactionInfo = {
+        '👍': messageLikesInfo,
+      };
+
+      expect(stringForReactionList(reactions)).toBe('👍 3');
+    },
+  );
+
+  it(
+    'should return (👍 3) for a message with three user likes' +
+      ' not including the viewer',
+    () => {
+      const messageLikesUsers = [
+        { id: '83810', isViewer: false, username: 'ginsu' },
+        { id: '86622', isViewer: false, username: 'ashoat' },
+        { id: '83889', isViewer: false, username: 'atul' },
+      ];
+      const messageLikesInfo = {
+        users: messageLikesUsers,
+        viewerReacted: false,
+      };
+
+      const reactions: ReactionInfo = {
+        '👍': messageLikesInfo,
+      };
+
+      expect(stringForReactionList(reactions)).toBe('👍 3');
+    },
+  );
+
+  it(
+    'should return (👍) for a message with one user like' +
+      ' including the viewer',
+    () => {
+      const messageLikesUsers = [
+        { id: '83810', isViewer: false, username: 'ginsu' },
+      ];
+      const messageLikesInfo = {
+        users: messageLikesUsers,
+        viewerReacted: true,
+      };
+
+      const reactions: ReactionInfo = {
+        '👍': messageLikesInfo,
+      };
+
+      expect(stringForReactionList(reactions)).toBe('👍');
+    },
+  );
+
+  it(
+    'should return (👍) for a message with one user like' +
+      ' not including the viewer',
+    () => {
+      const messageLikesUsers = [
+        { id: '83810', isViewer: false, username: 'ashoat' },
+      ];
+      const messageLikesInfo = {
+        users: messageLikesUsers,
+        viewerReacted: false,
+      };
+
+      const reactions: ReactionInfo = {
+        '👍': messageLikesInfo,
+      };
+
+      expect(stringForReactionList(reactions)).toBe('👍');
+    },
+  );
+
+  it('should return an empty string for a message no reactions', () => {
+    const reactions: ReactionInfo = {};
+
+    expect(stringForReactionList(reactions)).toBe('');
+  });
+
+  it(
+    'should return (👍 😆 3) for a message with one like not including' +
+      ' the viewer and three laugh reactions including the viewer',
+    () => {
+      const messageLikesUsers = [
+        { id: '83810', isViewer: false, username: 'varun' },
+      ];
+      const messageLikesInfo = {
+        users: messageLikesUsers,
+        viewerReacted: false,
+      };
+
+      const messageLaughsUsers = [
+        { id: '12345', isViewer: true, username: 'ginsu' },
+        { id: '67890', isViewer: false, username: 'ashoat' },
+        { id: '83889', isViewer: false, username: 'atul' },
+      ];
+      const messageLaughsInfo = {
+        users: messageLaughsUsers,
+        viewerReacted: true,
+      };
+
+      const reactions: ReactionInfo = {
+        '👍': messageLikesInfo,
+        '😆': messageLaughsInfo,
+      };
+
+      expect(stringForReactionList(reactions)).toBe('👍 😆 3');
+    },
+  );
+
+  it(
+    'should return (👍 9+) for a message with 12 user likes' +
+      ' not including the viewer',
+    () => {
+      const messageLikesUsers = [
+        { id: '86622', isViewer: false, username: 'ginsu' },
+        { id: '12345', isViewer: false, username: 'ashoat' },
+        { id: '67890', isViewer: false, username: 'atul' },
+        { id: '83889', isViewer: false, username: 'varun' },
+        { id: '49203', isViewer: false, username: 'tomek' },
+        { id: '83029', isViewer: false, username: 'max' },
+        { id: '72902', isViewer: false, username: 'jon' },
+        { id: '49022', isViewer: false, username: 'mark' },
+        { id: '48902', isViewer: false, username: 'kamil' },
+        { id: '80922', isViewer: false, username: 'marcin' },
+        { id: '12890', isViewer: false, username: 'inka' },
+        { id: '67891', isViewer: false, username: 'przemek' },
+      ];
+      const messageLikesInfo = {
+        users: messageLikesUsers,
+        viewerReacted: false,
+      };
+
+      const reactions: ReactionInfo = {
+        '👍': messageLikesInfo,
+      };
+
+      expect(stringForReactionList(reactions)).toBe('👍 9+');
+    },
+  );
+});
diff --git a/native/chat/composed-message.react.js b/native/chat/composed-message.react.js
--- a/native/chat/composed-message.react.js
+++ b/native/chat/composed-message.react.js
@@ -138,7 +138,10 @@
     );
 
     let inlineEngagement = null;
-    if (item.threadCreatedFromMessage || item.reactions.size > 0) {
+    if (
+      item.threadCreatedFromMessage ||
+      Object.keys(item.reactions).length > 0
+    ) {
       const positioning = isViewer ? 'right' : 'left';
       const inlineEngagementPositionStyle =
         positioning === 'left'
diff --git a/native/chat/inline-engagement.react.js b/native/chat/inline-engagement.react.js
--- a/native/chat/inline-engagement.react.js
+++ b/native/chat/inline-engagement.react.js
@@ -9,7 +9,7 @@
 } from 'react-native-reanimated';
 
 import useInlineEngagementText from 'lib/hooks/inline-engagement-text.react.js';
-import type { MessageReactionInfo } from 'lib/selectors/chat-selectors.js';
+import type { ReactionInfo } from 'lib/selectors/chat-selectors.js';
 import { stringForReactionList } from 'lib/shared/reaction-utils.js';
 import type { ThreadInfo } from 'lib/types/thread-types.js';
 
@@ -28,7 +28,7 @@
 
 type Props = {
   +threadInfo: ?ThreadInfo,
-  +reactions?: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions?: ReactionInfo,
   +disabled?: boolean,
 };
 function InlineEngagement(props: Props): React.Node {
@@ -88,7 +88,7 @@
   );
 
   const reactionList = React.useMemo(() => {
-    if (!reactions || reactions.size === 0) {
+    if (!reactions || Object.keys(reactions).length === 0) {
       return null;
     }
 
diff --git a/native/chat/message-reactions-modal.react.js b/native/chat/message-reactions-modal.react.js
--- a/native/chat/message-reactions-modal.react.js
+++ b/native/chat/message-reactions-modal.react.js
@@ -6,7 +6,7 @@
 import { View, Text, FlatList, TouchableHighlight } from 'react-native';
 import { SafeAreaView } from 'react-native-safe-area-context';
 
-import type { MessageReactionInfo } from 'lib/selectors/chat-selectors.js';
+import type { ReactionInfo } from 'lib/selectors/chat-selectors.js';
 import { useMessageReactionsList } from 'lib/shared/reaction-utils.js';
 
 import Modal from '../components/modal.react.js';
@@ -15,7 +15,7 @@
 import { useColors, useStyles } from '../themes/colors.js';
 
 export type MessageReactionsModalParams = {
-  +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions: ReactionInfo,
 };
 
 type Props = {
diff --git a/native/chat/multimedia-message-utils.js b/native/chat/multimedia-message-utils.js
--- a/native/chat/multimedia-message-utils.js
+++ b/native/chat/multimedia-message-utils.js
@@ -117,7 +117,7 @@
   if (multimediaMessageSendFailed(item)) {
     height += failedSendHeight;
   }
-  if (item.threadCreatedFromMessage || item.reactions.size > 0) {
+  if (item.threadCreatedFromMessage || Object.keys(item.reactions).length > 0) {
     height +=
       inlineEngagementStyle.height +
       inlineEngagementStyle.marginTop +
diff --git a/native/chat/reaction-message-utils.js b/native/chat/reaction-message-utils.js
--- a/native/chat/reaction-message-utils.js
+++ b/native/chat/reaction-message-utils.js
@@ -8,7 +8,7 @@
   sendReactionMessage,
   sendReactionMessageActionTypes,
 } from 'lib/actions/message-actions.js';
-import type { MessageReactionInfo } from 'lib/selectors/chat-selectors.js';
+import type { ReactionInfo } from 'lib/selectors/chat-selectors.js';
 import { messageTypes } from 'lib/types/message-types.js';
 import type { RawReactionMessageInfo } from 'lib/types/messages/reaction.js';
 import {
@@ -28,7 +28,7 @@
   messageID: ?string,
   localID: string,
   threadID: string,
-  reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  reactions: ReactionInfo,
 ): (reaction: string) => mixed {
   const viewerID = useSelector(
     state => state.currentUserInfo && state.currentUserInfo.id,
@@ -45,7 +45,9 @@
 
       invariant(viewerID, 'viewerID should be set');
 
-      const viewerReacted = reactions.get(reaction)?.viewerReacted;
+      const viewerReacted = reactions[reaction]
+        ? reactions[reaction].viewerReacted
+        : false;
       const action = viewerReacted ? 'remove_reaction' : 'add_reaction';
 
       const reactionMessagePromise = (async () => {
diff --git a/native/chat/robotext-message.react.js b/native/chat/robotext-message.react.js
--- a/native/chat/robotext-message.react.js
+++ b/native/chat/robotext-message.react.js
@@ -53,7 +53,7 @@
 
   const styles = useStyles(unboundStyles);
   let inlineEngagement = null;
-  if (item.threadCreatedFromMessage || item.reactions.size > 0) {
+  if (item.threadCreatedFromMessage || Object.keys(item.reactions).length > 0) {
     inlineEngagement = (
       <View style={styles.sidebar}>
         <InlineEngagement
diff --git a/native/chat/utils.js b/native/chat/utils.js
--- a/native/chat/utils.js
+++ b/native/chat/utils.js
@@ -67,7 +67,7 @@
   if (textMessageSendFailed(item)) {
     height += failedSendHeight;
   }
-  if (item.threadCreatedFromMessage || item.reactions.size > 0) {
+  if (item.threadCreatedFromMessage || Object.keys(item.reactions).length > 0) {
     height +=
       inlineEngagementStyle.height +
       inlineEngagementStyle.marginTop +
@@ -79,7 +79,7 @@
 function robotextMessageItemHeight(
   item: ChatRobotextMessageInfoItemWithHeight,
 ): number {
-  if (item.threadCreatedFromMessage || item.reactions.size > 0) {
+  if (item.threadCreatedFromMessage || Object.keys(item.reactions).length > 0) {
     return item.contentHeight + inlineEngagementStyle.height;
   }
   return item.contentHeight;
diff --git a/native/types/chat-types.js b/native/types/chat-types.js
--- a/native/types/chat-types.js
+++ b/native/types/chat-types.js
@@ -1,6 +1,6 @@
 // @flow
 
-import type { MessageReactionInfo } from 'lib/selectors/chat-selectors.js';
+import type { ReactionInfo } from 'lib/selectors/chat-selectors.js';
 import type {
   LocalMessageInfo,
   MultimediaMessageInfo,
@@ -23,7 +23,7 @@
   +robotext: EntityText,
   +threadCreatedFromMessage: ?ThreadInfo,
   +contentHeight: number,
-  +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions: ReactionInfo,
 };
 
 export type ChatTextMessageInfoItemWithHeight = {
@@ -37,7 +37,7 @@
   +endsCluster: boolean,
   +contentHeight: number,
   +threadCreatedFromMessage: ?ThreadInfo,
-  +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions: ReactionInfo,
 };
 
 export type MultimediaContentSizes = {
@@ -57,7 +57,7 @@
   +endsCluster: boolean,
   +threadCreatedFromMessage: ?ThreadInfo,
   +pendingUploads: ?MessagePendingUploads,
-  +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions: ReactionInfo,
 };
 
 export type ChatMessageInfoItemWithHeight =
diff --git a/web/chat/composed-message.react.js b/web/chat/composed-message.react.js
--- a/web/chat/composed-message.react.js
+++ b/web/chat/composed-message.react.js
@@ -123,7 +123,7 @@
     let inlineEngagement = null;
     if (
       (this.props.containsInlineEngagement && item.threadCreatedFromMessage) ||
-      item.reactions.size > 0
+      Object.keys(item.reactions).length > 0
     ) {
       const positioning = isViewer ? 'right' : 'left';
       inlineEngagement = (
diff --git a/web/chat/inline-engagement.react.js b/web/chat/inline-engagement.react.js
--- a/web/chat/inline-engagement.react.js
+++ b/web/chat/inline-engagement.react.js
@@ -5,7 +5,7 @@
 
 import { useModalContext } from 'lib/components/modal-provider.react.js';
 import useInlineEngagementText from 'lib/hooks/inline-engagement-text.react.js';
-import type { MessageReactionInfo } from 'lib/selectors/chat-selectors.js';
+import type { ReactionInfo } from 'lib/selectors/chat-selectors.js';
 import { stringForReactionList } from 'lib/shared/reaction-utils.js';
 import type { ThreadInfo } from 'lib/types/thread-types.js';
 
@@ -16,7 +16,7 @@
 
 type Props = {
   +threadInfo: ?ThreadInfo,
-  +reactions?: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions?: ReactionInfo,
   +positioning: 'left' | 'center' | 'right',
 };
 function InlineEngagement(props: Props): React.Node {
@@ -33,7 +33,7 @@
     },
   ]);
 
-  const reactionsExist = reactions && reactions.size > 0;
+  const reactionsExist = reactions && Object.keys(reactions).length > 0;
 
   const threadsContainerClasses = classNames({
     [css.threadsContainer]: threadInfo && !reactionsExist,
@@ -74,7 +74,7 @@
   );
 
   const reactionsList = React.useMemo(() => {
-    if (!reactions || reactions.size === 0) {
+    if (!reactions || Object.keys(reactions).length === 0) {
       return null;
     }
 
diff --git a/web/chat/message-tooltip.react.js b/web/chat/message-tooltip.react.js
--- a/web/chat/message-tooltip.react.js
+++ b/web/chat/message-tooltip.react.js
@@ -121,7 +121,10 @@
   const onEmojiSelect = React.useCallback(
     emoji => {
       const reactionInput = emoji.native;
-      const viewerReacted = !!reactions.get(reactionInput)?.viewerReacted;
+
+      const viewerReacted = reactions[reactionInput]
+        ? reactions[reactionInput].viewerReacted
+        : false;
       const action = viewerReacted ? 'remove_reaction' : 'add_reaction';
 
       sendReaction(reactionInput, action);
diff --git a/web/chat/robotext-message.react.js b/web/chat/robotext-message.react.js
--- a/web/chat/robotext-message.react.js
+++ b/web/chat/robotext-message.react.js
@@ -38,7 +38,7 @@
   let inlineEngagement;
   const { item } = props;
   const { threadCreatedFromMessage, reactions } = item;
-  if (threadCreatedFromMessage || reactions.size > 0) {
+  if (threadCreatedFromMessage || Object.keys(reactions).length > 0) {
     inlineEngagement = (
       <div className={css.sidebarMarginTop}>
         <InlineEngagement
diff --git a/web/modals/chat/message-reactions-modal.react.js b/web/modals/chat/message-reactions-modal.react.js
--- a/web/modals/chat/message-reactions-modal.react.js
+++ b/web/modals/chat/message-reactions-modal.react.js
@@ -2,7 +2,7 @@
 
 import * as React from 'react';
 
-import type { MessageReactionInfo } from 'lib/selectors/chat-selectors.js';
+import type { ReactionInfo } from 'lib/selectors/chat-selectors.js';
 import { useMessageReactionsList } from 'lib/shared/reaction-utils.js';
 
 import css from './message-reactions-modal.css';
@@ -10,7 +10,7 @@
 
 type Props = {
   +onClose: () => void,
-  +reactions: $ReadOnlyMap<string, MessageReactionInfo>,
+  +reactions: ReactionInfo,
 };
 
 function MessageReactionsModal(props: Props): React.Node {