nits fixes

res/css/views/messages/_MessageActionBar.pcss

@@ -21,6 +21,7 @@ limitations under the License.
     --MessageActionBar-item-hover-background: $panel-actions;
     --MessageActionBar-item-hover-borderRadius: 6px;
     --MessageActionBar-item-hover-zIndex: 1;
+    --MessageActionBar-star-button-color: #ffa534;
 
     position: absolute;
     visibility: hidden;
@@ -114,6 +115,14 @@ limitations under the License.
             }
         }
 
+        &.mx_MessageActionBar_favouriteButton::after {
+            mask-image: url('$(res)/img/element-icons/room/message-bar/star.svg');
+        }
+
+        &.mx_MessageActionBar_favouriteButton_fillstar::after {
+            background-color: var(--MessageActionBar-star-button-color);
+        }
+
         &.mx_MessageActionBar_editButton::after {
             mask-image: url('$(res)/img/element-icons/room/message-bar/edit.svg');
         }

res/img/element-icons/room/message-bar/star.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg"  width="21.87" height="20.801"><path d="m4.178 20.801 6.758-4.91 6.756 4.91-2.58-7.946 6.758-4.91h-8.352L10.936 0 8.354 7.945H0l6.758 4.91-2.58 7.946z"/></svg> 

src/components/views/messages/MessageActionBar.tsx

@@ -48,6 +48,7 @@ import { ALTERNATE_KEY_NAME } from "../../../accessibility/KeyboardShortcuts";
 import { UserTab } from '../dialogs/UserTab';
 import { Action } from '../../../dispatcher/actions';
 import SdkConfig from "../../../SdkConfig";
+import useFavouriteMessages from '../../../hooks/useFavouriteMessages';
 
 interface IOptionsButtonProps {
     mxEvent: MatrixEvent;
@@ -237,6 +238,26 @@ const ReplyInThreadButton = ({ mxEvent }: IReplyInThreadButton) => {
     </RovingAccessibleTooltipButton>;
 };
 
+interface IFavouriteButtonProp {
+    mxEvent: MatrixEvent;
+}
+
+const FavouriteButton = ({ mxEvent }: IFavouriteButtonProp) => {
+    const { isFavourite, toggleFavourite } = useFavouriteMessages();
+
+    const eventId = mxEvent.getId();
+    const classes = classNames("mx_MessageActionBar_maskButton mx_MessageActionBar_favouriteButton", {
+        'mx_MessageActionBar_favouriteButton_fillstar': isFavourite(eventId),
+    });
+
+    return <RovingAccessibleTooltipButton
+        className={classes}
+        title={_t("Favourite")}
+        onClick={() => toggleFavourite(eventId)}
+        data-testid={eventId}
+    />;
+};
+
 interface IMessageActionBarProps {
     mxEvent: MatrixEvent;
     reactions?: Relations;
@@ -421,6 +442,7 @@ export default class MessageActionBar extends React.PureComponent<IMessageAction
                 // Like the resend button, the react and reply buttons need to appear before the edit.
                 // The only catch is we do the reply button first so that we can make sure the react
                 // button is the very first button without having to do length checks for `splice()`.
+
                 if (this.context.canSendMessages) {
                     if (this.showReplyInThreadAction) {
                         toolbarOpts.splice(0, 0, threadTooltipButton);
@@ -442,6 +464,11 @@ export default class MessageActionBar extends React.PureComponent<IMessageAction
                         key="react"
                     />);
                 }
+                if (SettingsStore.getValue("feature_favourite_messages")) {
+                    toolbarOpts.splice(-1, 0, (
+                        <FavouriteButton key="favourite" mxEvent={this.props.mxEvent} />
+                    ));
+                }
 
                 // XXX: Assuming that the underlying tile will be a media event if it is eligible media.
                 if (MediaEventHelper.isEligible(this.props.mxEvent)) {

src/hooks/useFavouriteMessages.ts

@@ -0,0 +1,41 @@
+
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { useState } from "react";
+
+const favouriteMessageIds = JSON.parse(
+    localStorage?.getItem("io_element_favouriteMessages")?? "[]") as string[];
+
+export default function useFavouriteMessages() {
+    const [, setX] = useState<string[]>();
+
+    //checks if an id already exist
+    const isFavourite = (eventId: string): boolean => favouriteMessageIds.includes(eventId);
+
+    const toggleFavourite = (eventId: string) => {
+        isFavourite(eventId) ? favouriteMessageIds.splice(favouriteMessageIds.indexOf(eventId), 1)
+            : favouriteMessageIds.push(eventId);
+
+        //update the local storage
+        localStorage.setItem('io_element_favouriteMessages', JSON.stringify(favouriteMessageIds));
+
+        // This forces a re-render to account for changes in appearance in real-time when the favourite button is toggled
+        setX([]);
+    };
+
+    return { isFavourite, toggleFavourite };
+}

src/i18n/strings/en_EN.json

@@ -902,6 +902,7 @@
     "Right-click message context menu": "Right-click message context menu",
     "Location sharing - pin drop": "Location sharing - pin drop",
     "Live Location Sharing (temporary implementation: locations persist in room history)": "Live Location Sharing (temporary implementation: locations persist in room history)",
+    "Favourite Messages (under active development)": "Favourite Messages (under active development)",
     "Font size": "Font size",
     "Use custom size": "Use custom size",
     "Enable Emoji suggestions while typing": "Enable Emoji suggestions while typing",
@@ -2115,6 +2116,7 @@
     "Can't create a thread from an event with an existing relation": "Can't create a thread from an event with an existing relation",
     "Beta feature": "Beta feature",
     "Beta feature. Click to learn more.": "Beta feature. Click to learn more.",
+    "Favourite": "Favourite",
     "Edit": "Edit",
     "Reply": "Reply",
     "Collapse quotes": "Collapse quotes",
@@ -2940,7 +2942,6 @@
     "Copy link": "Copy link",
     "Forget": "Forget",
     "Favourited": "Favourited",
-    "Favourite": "Favourite",
     "Mentions only": "Mentions only",
     "Copy room link": "Copy room link",
     "Low Priority": "Low Priority",

src/settings/Settings.tsx

@@ -429,6 +429,13 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         ),
         default: false,
     },
+    "feature_favourite_messages": {
+        isFeature: true,
+        labsGroup: LabGroup.Messaging,
+        supportedLevels: LEVELS_FEATURE,
+        displayName: _td("Favourite Messages (under active development)"),
+        default: false,
+    },
     "baseFontSize": {
         displayName: _td("Font size"),
         supportedLevels: LEVELS_ACCOUNT_SETTINGS,

test/components/views/messages/MessageActionBar-test.tsx

@@ -59,6 +59,7 @@ describe('<MessageActionBar />', () => {
             msgtype: MsgType.Text,
             body: 'Hello',
         },
+        event_id: "$alices_message",
     });
 
     const bobsMessageEvent = new MatrixEvent({
@@ -69,6 +70,7 @@ describe('<MessageActionBar />', () => {
             msgtype: MsgType.Text,
             body: 'I am bob',
         },
+        event_id: "$bobs_message",
     });
 
     const redactedEvent = new MatrixEvent({
@@ -82,6 +84,25 @@ describe('<MessageActionBar />', () => {
         ...mockClientMethodsEvents(),
         getRoom: jest.fn(),
     });
+
+    const localStorageMock = (() => {
+        let store = {};
+        return {
+            getItem: jest.fn().mockImplementation(key => store[key] ?? null),
+            setItem: jest.fn().mockImplementation((key, value) => {
+                store[key] = value;
+            }),
+            clear: jest.fn().mockImplementation(() => {
+                store = {};
+            }),
+            removeItem: jest.fn().mockImplementation((key) => delete store[key]),
+        };
+    })();
+    Object.defineProperty(window, 'localStorage', {
+        value: localStorageMock,
+        writable: true,
+    });
+
     const room = new Room(roomId, client, userId);
     jest.spyOn(room, 'getPendingEvents').mockReturnValue([]);
 
@@ -464,4 +485,86 @@ describe('<MessageActionBar />', () => {
             });
         });
     });
+
+    describe('favourite button', () => {
+        //for multiple event usecase
+        const favButton = (evt: MatrixEvent) => {
+            return getComponent({ mxEvent: evt }).getByTestId(evt.getId());
+        };
+
+        describe('when favourite_messages feature is enabled', () => {
+            beforeEach(() => {
+                jest.spyOn(SettingsStore, 'getValue')
+                    .mockImplementation(setting => setting === 'feature_favourite_messages');
+                localStorageMock.clear();
+            });
+
+            it('renders favourite button on own actionable event', () => {
+                const { queryByLabelText } = getComponent({ mxEvent: alicesMessageEvent });
+                expect(queryByLabelText('Favourite')).toBeTruthy();
+            });
+
+            it('renders favourite button on other actionable events', () => {
+                const { queryByLabelText } = getComponent({ mxEvent: bobsMessageEvent });
+                expect(queryByLabelText('Favourite')).toBeTruthy();
+            });
+
+            it('does not render Favourite button on non-actionable event', () => {
+                //redacted event is not actionable
+                const { queryByLabelText } = getComponent({ mxEvent: redactedEvent });
+                expect(queryByLabelText('Favourite')).toBeFalsy();
+            });
+
+            it('remembers favourited state of multiple events, and handles the localStorage of the events accordingly',
+                () => {
+                    const alicesAction = favButton(alicesMessageEvent);
+                    const bobsAction = favButton(bobsMessageEvent);
+
+                    //default state before being clicked
+                    expect(alicesAction.classList).not.toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(bobsAction.classList).not.toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(localStorageMock.getItem('io_element_favouriteMessages')).toBeNull();
+
+                    //if only alice's event is fired
+                    act(() => {
+                        fireEvent.click(alicesAction);
+                    });
+
+                    expect(alicesAction.classList).toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(bobsAction.classList).not.toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(localStorageMock.setItem)
+                        .toHaveBeenCalledWith('io_element_favouriteMessages', '["$alices_message"]');
+
+                    //when bob's event is fired,both should be styled and stored in localStorage
+                    act(() => {
+                        fireEvent.click(bobsAction);
+                    });
+
+                    expect(alicesAction.classList).toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(bobsAction.classList).toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(localStorageMock.setItem)
+                        .toHaveBeenCalledWith('io_element_favouriteMessages', '["$alices_message","$bobs_message"]');
+
+                    //finally, at this point the localStorage should contain the two eventids
+                    expect(localStorageMock.getItem('io_element_favouriteMessages'))
+                        .toEqual('["$alices_message","$bobs_message"]');
+
+                    //if decided to unfavourite bob's event by clicking again
+                    act(() => {
+                        fireEvent.click(bobsAction);
+                    });
+                    expect(bobsAction.classList).not.toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(alicesAction.classList).toContain('mx_MessageActionBar_favouriteButton_fillstar');
+                    expect(localStorageMock.getItem('io_element_favouriteMessages')).toEqual('["$alices_message"]');
+                });
+        });
+
+        describe('when favourite_messages feature is disabled', () => {
+            it('does not render', () => {
+                jest.spyOn(SettingsStore, 'getValue').mockReturnValue(false);
+                const { queryByLabelText } = getComponent({ mxEvent: alicesMessageEvent });
+                expect(queryByLabelText('Favourite')).toBeFalsy();
+            });
+        });
+    });
 });