Convert MessagePanel to React class

I was about to add the getDerivedStateFromProps function to change
how read markers worked, but doing that in an old style class
means the statics object, so let;s just convert the thing.

src/components/structures/MessagePanel.js

@@ -1,6 +1,7 @@
 /*
 Copyright 2016 OpenMarket Ltd
 Copyright 2018 New Vector Ltd
+Copyright 2019 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.
@@ -18,7 +19,6 @@ limitations under the License.
 /* global Velocity */
 
 import React from 'react';
-import createReactClass from 'create-react-class';
 import ReactDOM from 'react-dom';
 import PropTypes from 'prop-types';
 import classNames from 'classnames';
@@ -37,10 +37,8 @@ const isMembershipChange = (e) => e.getType() === 'm.room.member' || e.getType()
 
 /* (almost) stateless UI component which builds the event tiles in the room timeline.
  */
-module.exports = createReactClass({
-    displayName: 'MessagePanel',
-
-    propTypes: {
+export default class MessagePanel extends React.Component {
+    propTypes = {
         // true to give the component a 'display: none' style.
         hidden: PropTypes.bool,
 
@@ -109,9 +107,9 @@ module.exports = createReactClass({
 
         // whether to show reactions for an event
         showReactions: PropTypes.bool,
-    },
+    };
 
-    componentWillMount: function() {
+    componentDidMount() {
         // the event after which we put a visible unread marker on the last
         // render cycle; null if readMarkerVisible was false or the RM was
         // suppressed (eg because it was at the end of the timeline)
@@ -168,37 +166,37 @@ module.exports = createReactClass({
             SettingsStore.getValue("showHiddenEventsInTimeline");
 
         this._isMounted = true;
-    },
+    }
 
-    componentWillUnmount: function() {
+    componentWillUnmount() {
         this._isMounted = false;
-    },
+    }
 
     /* get the DOM node representing the given event */
-    getNodeForEventId: function(eventId) {
+    getNodeForEventId(eventId) {
         if (!this.eventNodes) {
             return undefined;
         }
 
         return this.eventNodes[eventId];
-    },
+    }
 
     /* return true if the content is fully scrolled down right now; else false.
      */
-    isAtBottom: function() {
+    isAtBottom() {
         return this.refs.scrollPanel
             && this.refs.scrollPanel.isAtBottom();
-    },
+    }
 
     /* get the current scroll state. See ScrollPanel.getScrollState for
      * details.
      *
      * returns null if we are not mounted.
      */
-    getScrollState: function() {
+    getScrollState() {
         if (!this.refs.scrollPanel) { return null; }
         return this.refs.scrollPanel.getScrollState();
-    },
+    }
 
     // returns one of:
     //
@@ -206,7 +204,7 @@ module.exports = createReactClass({
     //  -1: read marker is above the window
     //   0: read marker is within the window
     //  +1: read marker is below the window
-    getReadMarkerPosition: function() {
+    getReadMarkerPosition() {
         const readMarker = this.refs.readMarkerNode;
         const messageWrapper = this.refs.scrollPanel;
 
@@ -226,45 +224,45 @@ module.exports = createReactClass({
         } else {
             return 1;
         }
-    },
+    }
 
     /* jump to the top of the content.
      */
-    scrollToTop: function() {
+    scrollToTop() {
         if (this.refs.scrollPanel) {
             this.refs.scrollPanel.scrollToTop();
         }
-    },
+    }
 
     /* jump to the bottom of the content.
      */
-    scrollToBottom: function() {
+    scrollToBottom() {
         if (this.refs.scrollPanel) {
             this.refs.scrollPanel.scrollToBottom();
         }
-    },
+    }
 
     /**
      * Page up/down.
      *
      * @param {number} mult: -1 to page up, +1 to page down
      */
-    scrollRelative: function(mult) {
+    scrollRelative(mult) {
         if (this.refs.scrollPanel) {
             this.refs.scrollPanel.scrollRelative(mult);
         }
-    },
+    }
 
     /**
      * Scroll up/down in response to a scroll key
      *
      * @param {KeyboardEvent} ev: the keyboard event to handle
      */
-    handleScrollKey: function(ev) {
+    handleScrollKey(ev) {
         if (this.refs.scrollPanel) {
             this.refs.scrollPanel.handleScrollKey(ev);
         }
-    },
+    }
 
     /* jump to the given event id.
      *
@@ -276,33 +274,33 @@ module.exports = createReactClass({
      * node (specifically, the bottom of it) will be positioned. If omitted, it
      * defaults to 0.
      */
-    scrollToEvent: function(eventId, pixelOffset, offsetBase) {
+    scrollToEvent(eventId, pixelOffset, offsetBase) {
         if (this.refs.scrollPanel) {
             this.refs.scrollPanel.scrollToToken(eventId, pixelOffset, offsetBase);
         }
-    },
+    }
 
-    scrollToEventIfNeeded: function(eventId) {
+    scrollToEventIfNeeded(eventId) {
         const node = this.eventNodes[eventId];
         if (node) {
             node.scrollIntoView({block: "nearest", behavior: "instant"});
         }
-    },
+    }
 
     /* check the scroll state and send out pagination requests if necessary.
      */
-    checkFillState: function() {
+    checkFillState() {
         if (this.refs.scrollPanel) {
             this.refs.scrollPanel.checkFillState();
         }
-    },
+    }
 
-    _isUnmounting: function() {
+    _isUnmounting() {
         return !this._isMounted;
-    },
+    }
 
     // TODO: Implement granular (per-room) hide options
-    _shouldShowEvent: function(mxEv) {
+    _shouldShowEvent(mxEv) {
         if (mxEv.sender && MatrixClientPeg.get().isUserIgnored(mxEv.sender.userId)) {
             return false; // ignored = no show (only happens if the ignore happens after an event was received)
         }
@@ -320,9 +318,9 @@ module.exports = createReactClass({
         if (this.props.highlightedEventId === mxEv.getId()) return true;
 
         return !shouldHideEvent(mxEv);
-    },
+    }
 
-    _getEventTiles: function() {
+    _getEventTiles() {
         const DateSeparator = sdk.getComponent('messages.DateSeparator');
         const EventListSummary = sdk.getComponent('views.elements.EventListSummary');
         const MemberEventListSummary = sdk.getComponent('views.elements.MemberEventListSummary');
@@ -596,9 +594,9 @@ module.exports = createReactClass({
 
         this.currentReadMarkerEventId = readMarkerVisible ? this.props.readMarkerEventId : null;
         return ret;
-    },
+    }
 
-    _getTilesForEvent: function(prevEvent, mxEv, last) {
+    _getTilesForEvent(prevEvent, mxEv, last) {
         const EventTile = sdk.getComponent('rooms.EventTile');
         const DateSeparator = sdk.getComponent('messages.DateSeparator');
         const ret = [];
@@ -691,20 +689,20 @@ module.exports = createReactClass({
         );
 
         return ret;
-    },
+    }
 
-    _wantsDateSeparator: function(prevEvent, nextEventDate) {
+    _wantsDateSeparator(prevEvent, nextEventDate) {
         if (prevEvent == null) {
             // first event in the panel: depends if we could back-paginate from
             // here.
             return !this.props.suppressFirstDateSeparator;
         }
         return wantsDateSeparator(prevEvent.getDate(), nextEventDate);
-    },
+    }
 
     // Get a list of read receipts that should be shown next to this event
     // Receipts are objects which have a 'userId', 'roomMember' and 'ts'.
-    _getReadReceiptsForEvent: function(event) {
+    _getReadReceiptsForEvent(event) {
         const myUserId = MatrixClientPeg.get().credentials.userId;
 
         // get list of read receipts, sorted most recent first
@@ -728,12 +726,12 @@ module.exports = createReactClass({
             });
         });
         return receipts;
-    },
+    }
 
     // Get an object that maps from event ID to a list of read receipts that
     // should be shown next to that event. If a hidden event has read receipts,
     // they are folded into the receipts of the last shown event.
-    _getReadReceiptsByShownEvent: function() {
+    _getReadReceiptsByShownEvent() {
         const receiptsByEvent = {};
         const receiptsByUserId = {};
 
@@ -786,9 +784,9 @@ module.exports = createReactClass({
         }
 
         return receiptsByEvent;
-    },
+    }
 
-    _getReadMarkerTile: function(visible) {
+    _getReadMarkerTile(visible) {
         let hr;
         if (visible) {
             hr = <hr className="mx_RoomView_myReadMarker"
@@ -802,9 +800,9 @@ module.exports = createReactClass({
                 { hr }
             </li>
         );
-    },
+    }
 
-    _startAnimation: function(ghostNode) {
+    _startAnimation = (ghostNode) => {
         if (this._readMarkerGhostNode) {
             Velocity.Utilities.removeData(this._readMarkerGhostNode);
         }
@@ -816,9 +814,9 @@ module.exports = createReactClass({
                      {duration: 400, easing: 'easeInSine',
                       delay: 1000});
         }
-    },
+    };
 
-    _getReadMarkerGhostTile: function() {
+    _getReadMarkerGhostTile() {
         const hr = <hr className="mx_RoomView_myReadMarker"
                   style={{opacity: 1, width: '99%'}}
                   ref={this._startAnimation}
@@ -833,31 +831,31 @@ module.exports = createReactClass({
                 { hr }
             </li>
         );
-    },
+    }
 
-    _collectEventNode: function(eventId, node) {
+    _collectEventNode = (eventId, node) => {
         this.eventNodes[eventId] = node;
-    },
+    }
 
     // once dynamic content in the events load, make the scrollPanel check the
     // scroll offsets.
-    _onHeightChanged: function() {
+    _onHeightChanged = () => {
         const scrollPanel = this.refs.scrollPanel;
         if (scrollPanel) {
             scrollPanel.checkScroll();
         }
-    },
+    };
 
-    _onTypingShown: function() {
+    _onTypingShown = () => {
         const scrollPanel = this.refs.scrollPanel;
         // this will make the timeline grow, so checkScroll
         scrollPanel.checkScroll();
         if (scrollPanel && scrollPanel.getScrollState().stuckAtBottom) {
             scrollPanel.preventShrinking();
         }
-    },
+    };
 
-    _onTypingHidden: function() {
+    _onTypingHidden = () => {
         const scrollPanel = this.refs.scrollPanel;
         if (scrollPanel) {
             // as hiding the typing notifications doesn't
@@ -868,9 +866,9 @@ module.exports = createReactClass({
             // reveal added padding to balance the notifs disappearing.
             scrollPanel.checkScroll();
         }
-    },
+    };
 
-    updateTimelineMinHeight: function() {
+    updateTimelineMinHeight() {
         const scrollPanel = this.refs.scrollPanel;
 
         if (scrollPanel) {
@@ -885,16 +883,16 @@ module.exports = createReactClass({
                 scrollPanel.preventShrinking();
             }
         }
-    },
+    }
 
-    onTimelineReset: function() {
+    onTimelineReset() {
         const scrollPanel = this.refs.scrollPanel;
         if (scrollPanel) {
             scrollPanel.clearPreventShrinking();
         }
-    },
+    }
 
-    render: function() {
+    render() {
         const ScrollPanel = sdk.getComponent("structures.ScrollPanel");
         const WhoIsTypingTile = sdk.getComponent("rooms.WhoIsTypingTile");
         const Spinner = sdk.getComponent("elements.Spinner");
@@ -941,5 +939,5 @@ module.exports = createReactClass({
                 { bottomSpinner }
             </ScrollPanel>
         );
-    },
-});
+    }
+}