diff --git a/src/components/structures/FilePanel.js b/src/components/structures/FilePanel.js
index bb7c1f9642..244c361402 100644
--- a/src/components/structures/FilePanel.js
+++ b/src/components/structures/FilePanel.js
@@ -159,7 +159,7 @@ class FilePanel extends React.Component {
         }
     };
 
-    async updateTimelineSet(roomId: string) {
+    async updateTimelineSet(roomId) {
         const client = MatrixClientPeg.get();
         const room = client.getRoom(roomId);
         const eventIndex = EventIndexPeg.get();
diff --git a/src/components/views/context_menus/MessageContextMenu.js b/src/components/views/context_menus/MessageContextMenu.js
index 5d1aad0600..5bae1b5fdd 100644
--- a/src/components/views/context_menus/MessageContextMenu.js
+++ b/src/components/views/context_menus/MessageContextMenu.js
@@ -207,7 +207,7 @@ export default class MessageContextMenu extends React.Component {
         this.closeMenu();
     };
 
-    onPermalinkClick = (e: Event) => {
+    onPermalinkClick = (e) => {
         e.preventDefault();
         const ShareDialog = sdk.getComponent("dialogs.ShareDialog");
         Modal.createTrackedDialog('share room message dialog', '', ShareDialog, {
diff --git a/src/components/views/dialogs/TabbedIntegrationManagerDialog.js b/src/components/views/dialogs/TabbedIntegrationManagerDialog.js
index 618b0b4347..1d29ad8823 100644
--- a/src/components/views/dialogs/TabbedIntegrationManagerDialog.js
+++ b/src/components/views/dialogs/TabbedIntegrationManagerDialog.js
@@ -63,11 +63,11 @@ export default class TabbedIntegrationManagerDialog extends React.Component {
         };
     }
 
-    componentDidMount(): void {
+    componentDidMount() {
         this.openManager(0, true);
     }
 
-    openManager = async (i: number, force = false) => {
+    openManager = async (i, force = false) => {
         if (i === this.state.currentIndex && !force) return;
 
         const manager = this.state.managers[i];
diff --git a/src/components/views/elements/PersistedElement.js b/src/components/views/elements/PersistedElement.js
index 701c140a19..d1fc96e630 100644
--- a/src/components/views/elements/PersistedElement.js
+++ b/src/components/views/elements/PersistedElement.js
@@ -187,4 +187,4 @@ export default class PersistedElement extends React.Component {
     }
 }
 
-export const getPersistKey = (appId: string) => 'widget_' + appId;
+export const getPersistKey = (appId) => 'widget_' + appId;
diff --git a/src/components/views/groups/GroupInviteTile.js b/src/components/views/groups/GroupInviteTile.js
index bc0bf966f9..c4e1433316 100644
--- a/src/components/views/groups/GroupInviteTile.js
+++ b/src/components/views/groups/GroupInviteTile.js
@@ -32,7 +32,7 @@ import {mediaFromMxc} from "../../../customisations/Media";
 // XXX this class copies a lot from RoomTile.js
 @replaceableComponent("views.groups.GroupInviteTile")
 export default class GroupInviteTile extends React.Component {
-    static propTypes: {
+    static propTypes = {
         group: PropTypes.object.isRequired,
     };