Show a face pile on a space preview

src/components/views/elements/FacePile.tsx

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+/*
+Copyright 2021 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 React from "react";
+import { Room } from "matrix-js-sdk/src/models/room";
+
+import MemberAvatar from "../avatars/MemberAvatar";
+import { _t } from "../../../languageHandler";
+import DMRoomMap from "../../../utils/DMRoomMap";
+
+const DEFAULT_NUM_FACES = 5;
+
+interface IProps {
+    room: Room;
+    numShown?: number;
+}
+
+const FacePile = ({ room, numShown = DEFAULT_NUM_FACES }: IProps) => {
+    const knownMembers = room.getJoinedMembers().filter(member => {
+        return !!DMRoomMap.shared().getDMRoomsForUserId(member.userId)?.length;
+    });
+
+    if (knownMembers.length < 1) return null;
+    const shownMembers = knownMembers.slice(0, numShown);
+
+    return <div className="mx_FacePile">
+        <div className="mx_FacePile_faces">
+            { shownMembers.map(member => <MemberAvatar key={member.userId} member={member} width={28} height={28} />) }
+        </div>
+        <span>
+            { _t("%(count)s people you know have already joined", { count: knownMembers.length }) }
+        </span>
+    </div>
+};
+
+export default FacePile;